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A comparison of the inductive and the deductive methods in teaching two units of sequential mathematics… Holyoke, Frederick Vernon 1954

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A COMPARISON OF THE INDUCTIVE AND THE DEDUCTIVE METHODS IN TEACHING TWO UNITS OF SEQUENTIAL MATHEMATICS IN HETEROGENEOUS CLASSES OF THE SENIOR HIGH SCHOOL by FREDERICK VERNON HOLYOKE A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS In the School of EDUCATION We accept this thesis as conforming to the standard required from candidates for the degree of MASTER OF ARTS. Members of the School of Education THE UNIVERSITY OF BRITISH COLUMBIA Apr i l , 195k ABSTRACT Problem: Does the inductive method o f f e r advantages over the deductive f o r heterogeneous classes i n Senior High School mathematics? A proposal i s made that a l l students i n such classes s t a r t together with p r a c t i c a l applications and that each pro-ceed as f a r into theory as he i s able. There i s some question, however, as to whether the inductive order and s t y l e of pres-entation would r e s u l t i n loss of learning, e s p e c i a l l y i n the th e o r e t i c a l aspeets, as compared with the deductive method* To help answer this question a co n t r o l l e d experiment was conducted i n which two classes, equated by mean and stand-ard deviation on the bases of I.Q. and previous mathematics marks, worked during eight l\.0 minute periods on elementary trigonometry and during seven s i m i l a r periods on chords i n a c i r c l e . This subject matter, the same f o r both classes, formed part of t h e i r regular course i n Grade XI mathematics. The inductive group began with p r a c t i c a l applications and proceeded to theory while the deductive group followed the reverse order; both classes were held to the same length of time f o r each type of work, however. Mimeographed sheets were provided to pupils f o r each lesson. The groups were reversed as to method f o r the second u n i t . Teacheir-made tests were employed f o r measuring learning gain. The f i r s t unit of the experiment was l a t e r c a r r i e d on with sample classes i n two other schools. Results showed no s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r -ences i n general learning gain between the two methods. Results i n the f i r s t unit by the o r i g i n a l sample indicated no loss i n the t h e o r e t i c a l aspects under the induc-t i v e method. Information concerning t h i s feature was not available from the other groups or from the second u n i t . In general, the evidence favoured the n u l l hypothesis. i i TABLE OF CONTENTS Page CHAPTER I BACKGROUND OF THE PROBLEM Transition and Trends i n Secondary Mathematics 1 Limitations of the Double or Multiple Track System.... $ A Review of Attempts to Provide f o r Individual Differences.... 6 Organization of Subject Matter f o r Heterogeneous Classes.... 11 The Inductive vs the Deductive Approach 13 Summary If? Statement of the Problem i n the Present Investigation. 16 CHAPTER II PLAN, SETTING, AND LIMITATIONS OF THE STUDY General Plan 17 Setting f o r the Experiment 17 Design of the Experimental Study 19 Subject Matter 20 Measurement and Comparison 21 Limitations of the Study 21 CHAPTER III PROCEDURE Preparation of Material 23 Classroom Procedure. 29 Measurement 30 Administration 30 CHAPTER IV ANALYSIS OF RESULTS Equality of Groups. 3 i | General Achievement of Groups 36 Achievement In P r a c t i c a l and i n Theoretical Work 39 Correlation Between A b i l i t y and Achievement lj.1 i i i Page CHAPTER V SUMMARY AND CONCLUSIONS Summary of the Problem and Its Background lj.3 The Experiment • Equality of Groups ij.6 Measurement. 1+6 Summary of Results Ij-7 Interpretation of Results lj.8 Summary of Conclusions f>l C r i t i c a l Note and Suggestions for Further Study f?2 BIBLIOGRAPHY APPENDIX A MIMEOGRAPHED DETAIL OF LESSONS -. £9 APPENDIX B TESTS 6l APPENDIX C SAMPLE OF CALCULATIONS 62 i v LIST OP TABLES TABLE Page I Outline of Lesson Sequences -Elementary Trigonometry Unit 21+ II Outline of Lesson Sequences -Chords i n a C i r c l e Unit 25 III Preliminary Equating of Kamloops Groups 31 IV P i n a l Equating of Kamloops Groups 3i|. V Equating of Chilliwack Groups. 35 VI Equating of Langley Groups 35 VII General Achievement of Kamloops Groups i n Unit I..; 36 VIII General Achievement of Kamloops Groups In Unit I I . . 37 IX Test and Gain Differences - Unit II 37 X General Achievement of Chilliwack Groups i n Unit I. 38 XI General Achievement of Langley Groups In Unit I.... 38 XII Comparison of Mean Gains In General Learning 39 XIII Results In Theoretical and P r a c t i c a l Work Shown Separately lj.0 XIV Mean Score Differences Between P r a c t i c a l and Theoretical.... lj.0 XV Correlation Between I.Q. and Teat Score Gain 1+1 XVI Correlation Between I.Q,. and Test Marks - P r a c t i c a l and Theoretical - Unit I - Kamloops Groups 1+2 LIST OP ILLUSTRATIONS I Lesson 1, Sequence A 26 II Lesson 1, Sequence B 27 III Lesson 5 , Sequence A.. 28 V ACKNOWLEEG-MENTS The writer wishes to acknowledge the guidance, encouragement at points of d i f f i c u l t y , and insistence upon high standards both, i n research and i n expression, given by Dr. J. Ranton Mcintosh of the School of Education, the University of B r i t i s h Columbia, under whose d i r e c t i o n t h i s thesis was prepared. The writer wishes to acknowledge also the assistance of Miss M. ¥. How of Chilliwack, B. C and Mr. James P. Clark of Langley, B. C. who conducted the work of Unit I i n t h e i r respective High Schools, CHAPTER I BACKGROUND OP THE PROBLEM Transition and Trends i n Secondary Mathematics The retreat of t r a d i t i o n a l mathematics before the advance of modern psychology, the emphasis upon actual needs which forms part of our philosophy of education to-day, and the tremendous increase i n attendance at High Schools as they seek to provide f o r a l l youth have combined to bring about a great change i n secondary mathematics during the past several decades. And the movement i s not yet complete. Our whole secondary school system appears to be i n a t r a n s i t i o n a l stage and the mathematics phase of i t remains i n process of r e -organization. Current educational l i t e r a t u r e contains many expressions of opinion by leaders i n the mathematics teaching f i e l d ; the majority of these point towards common goals but remain consistently general. In development of programs and rebuilding of mathematics c u r r i c u l a trends have become f a i r l y well marked, but detailed surveys are few and construction i s almost e r r a t i c . In a f a i r l y recent a r t i c l e E. R. Breslich" 1" has traced the outstanding changes of the past f i f t y years, noting the development of general mathematics with emphasis upon ap-p l i c a t i o n s to daily l i f e , general c o r r e l a t i o n , the increase 1. B r e s l i c h , E. R., How Movements of Improvement Have Affected Present lay Teaching of Mathematics, Sch. S c i . & Math», Feb. 1951: 131-llp.. 2 of emphasis on meaning and understanding, greater stress on concrete materials, use of multi-sensory aids, and the project and laboratory methods to provide f o r i n d i v i d u a l differences, H. P. Fehr^ i n discussing a modern program compares the older aim of college preparation with that of mathematics f o r a l l members of society, yet stresses In the l a t t e r respect that p a l l are not a l i k e . P. S. Jones attempts to summarize such trends as teaching f o r meaning and understanding (both s o c i a l and mathematical), emphasis upon l o g i c , development of several types of course, enrichment materials, laboratory methods, use of Instruments and teaching aids, source units, and u t i l -i z a t i o n of applications. He notes that l i t t l e has been done to improve the sequential courses. W. D. Reeve-^ outlines such s i g n i f i c a n t trends as stress on meaning, general mathe-matics, multi-sensory aids, omissions and changed emphases i n p a r t i c u l a r features of subject matter, and recognition of i n -dividual differences; although he questions whether much more than l i p service has been paid to the l a s t named. Wm A. Gager' reports that a F l o r i d a workshop group studying improvement of 1. Fehr, H. P., A Proposal f o r a Modern Program i n Mathemat-i c a l Education i n the Secondary Schools, Sch. S c i . & Math., Dec. 1949: 723-730. 2 . Jones, P. S. and others, Report on Progress i n Mathematics Education, Sch. S c i . & Math., June 191+9: 1+65-1+71+. 3 . Reeve, • W. D., S i g n i f i c a n t Trends i n Secondary Mathematics, Sch. S c i . & Math., Mch. 19^9: 229-236. 1+. Gager, Wm A., Functional Mathematics, Math. Tch., May -1951: 297-301. 3 mathematics curricula favoured functional mathematics as a constant i n grades 7 to 10 and elective i n grades 11 and 12, with sequential algebra, geometry, and trigonometry from grades 9 to 12 also elective* While this was advocated, re-ported indications were that few schools had come close to the plan i n actual practice. The Commission on Post War Flans of the National Council of Teachers of Mathematics1 conducted an extensive survey* In their second report i n 19l|lj. they set forth the responsibility of the High School as twofold: to provide sound mathematical training f o r future leaders i n science, mathematics, and related f i e l d s , and to ensure mathematical competence i n ordinary affairs of l i f e for a l l * To meet this responsibility they recommended a unified program of general mathematics f o r grades 7 and 8, followed by a "double track" of sequential mathematics for those of higher a b i l i t y and of general mathematics for the remainder* H* Schorling, who was a member of the commission, later published an interpre-tation of some of their data, summarizing that two-thirds of the schools which had reported did offer the double track i n grade 9, and one-half carried i t on through grade 10, but a relatively small number provided any alternative to the single track of sequential mathematics courses i n grades 11 or 12* 1* Commission on Post War Plans - National Council of Teach-ers of. Mathematics, Second Report, Math* Teh*, May 19k$: 19^-221. 2. Schorling; R*, What's Going On i n Your School, Math. Tch*, Apr* 19P: llj.7-153. Quite recently, a report on a special research project, spon-sored by the Southern Section of the California Mathematics Council but carried on over thirty-five states, Indicated favour f o r a three track or a multiple track program,1 This report did not give a specific plan, and there does not appear to have been agreement upon organization details* It was re-commended that formal mathematics courses be strengthened and that there be "sequential ungraded courses In non-traditional mathematics.11 Beyond these appeared to be simply the aim to' expand general mathematics* It is noteworthy that a consid-erable number of the personnel engaged on this project had also been leading members of the Commission on Post War Plans* A l l these reports show considerable general accord, and from them the writer attempts to summarize presently es-tablished trends as follows: 1* Emphasis on meaning and understanding: a* more concrete illustrations and applications b* closer relation to real l i f e situations c* use of multi-sensory aids 2* Re-emphasis on c r i t i c a l thinking: a* Inclusion of non-mathematical subject matter b. teaching for transfer 3* General mathematics: a* decorapartmentalization of arithmetic, algebra, and geometry b* social value topics c. correlation with other subjects fy. Recognition of Individual differences 1* Irvin, Lee, The Organization of Instruction i n Arithmetic and Basic Mathematics i n Selected Secondary Schools, Math. Tch., Apr. 1953: 235-21+0. 5>. Curriculum reorganization: a* general mathematics - compulsory for grades 7 and 8 b. double track (expanding to multiple track) - for grades 9 to 12, one or two years compulsory. Limitations of the Double or Multiple Track System Looking more particularly at the Senior High School or at grades 9 to 12, while the double or multiple track seems a working attempt to meet the needs of our greatly increased and varied population, i t appears to have limitations. The Commission on Post War Plans 1 noted i n their survey that more than two-thirds of a l l High Schools had less than 200 students and eight teachers. To meet their situation, It was recom-mended that two courses be handled simultaneously by one tea-cher, that cycling of courses be carried on, and that use be 2 made of correspondence courses. Schorling later pointed out, however, that the response to the enquiry had been very weak from small High Schools. There seems reason to think, then, that the Commission's recommendations for them were not as adequately considered as was the general question. In order to provide a single track many small schools have used the practices recommended by the Commission. In these situations, where a teacher previously handled two courses simultaneously, the double or multiple track would require him to direct a variety of interests at once. 1. Commission on Post War Plans, op. c i t . 2. Schorling, R., op. c i t . 6 Even in the large schools which can offer a number of elective courses, guidance services are not perfect and social pressures exist, hence the composition of many classes appears l i k e l y to be quite heterogeneous for some time to come. There remains, then, a considerable problem of making reasonably adequate provision for the varied a b i l i t i e s , needs, and interests which occur within single classes. A Review of Attempts to Provide for Individual Differences A number of methods of providing for individual differences have been considered i n the past. An investig-ation of supervised study by Minniek as early as 1913 bas been reviewed by Heed*1, together with later ones by Jones and Douglass. Another by Johnson combined supervised study with a project method and socialized presentation. Stokes achieved unusual success with a low I.Q. class by individual instruc-tion. Reed'3 general summary of a l l these indicates some value in homogeneous grouping, supervised study, project method, differentiated assignments, individual Instruction, and special teaching for slow pupils. 2 The University of Chicago High School developed over some years a general pattern of supervised study with 1, Reed, Homer B., Psychology and Teaching of Secondary School Subjects, New York, Prentice-Hall, 1939. 2. university of Chicago, Mathematics Instruction i n the University High School, Pub. No. 8, Nov. 1910. 7 added Instruction for the weak and enrichment for students of high a b i l i t y ; they also found sectional grouping worthwhile* Brownman1 in a controlled study compared lecture-demonstration with the individual-laboratory method for teaching experiment-a l geometry, and he found the latter significantly superior 2 i n test scores and i n experimental concepts. Duroll consid-ered three stages of mastery and advocated gradation of exer-cises; this plan is used in a number of modem text-books. Lane^ graded original exercises i n plane geometry on three levels; i n an experimental class students were allowed to make their own selection so that those completing d i f f i c u l t exercises did not have to attempt the easier ones, while i n the control class students simply were assigned a certain number of exercises per day. According to her report, com-parison of test results gave indications of superiority for the experimental method except In the case of students of low a b i l i t y . She also reported that the majority of those who had choice of exercises appeared to select intelligently rather than l a z i l y . 1. Brownman,. David E», Measurable Outcomes of Two Methods of Teaching Experimental Geometry, Jnl, Exp. Ed., Sept. 1938: 31-31+. 2* Durell, Fletcher, Mathematical Adventures, Boston, Bruce Humphries, 1938: 60-75. 3. Lane, Ruth, The Use of Graded Originals i n Plane Geometry, Math. Tch., Nov. 191+0: 291-300. 8 Several more recent studies differ i n their treat-ment of individual differences, Albers and Seagoe1 i n a ninth grade algebra class allowed f i f t e e n minutes of each daily period to students whose I.Q, was 12£ or above for explorative enrichment on a more or less voluntary basis; a small library of enrichment material was provided and extra voluntary home-work allowed. In the control class the corresponding students carried on only regular work. In a f i n a l test on algebra achievement the experimental group showed progress equal to that of the control group, and In a further test on the en-richment material they showed good results. The conclusions were that superior students can afford time for enrichment, that such work i s self-motivating, and also that the procedure i s administratively possible i n small schools unable to use homogeneous grouping. But the findings of this study are 2 limited to students of superior a b i l i t y , Lee described a plan used by a large High School where several general or functional courses, each including some theoretical work, were carried on simultaneously with more formal offerings i n algebra and geometry. A l l these were organized on a semester basis, and a student showing Interest and a b i l i t y could move 1, Albers, M. E. and Seagoe, M, V., Enrichment for Superior Students i n Algebra Classes, Jnl. Ed, Rsch,, Mch. 191+7: 2, Lee, Wm, Provision for Individual Differences i n High School Mathematics Courses, Math, Tch,, Oct, 19U7: 291*-297. 9 from the general to the formal or vice versa at the beginning of any term. While the plan appears complicated and, i n the form described, limited to large schools, i t s mosaic pattern strikes the writer as uniquely apt for any heterogeneous group of developing youth. In a project by Fowler, 1 several features were combined i n an experimental procedure for teaching geometry. A mimeographed syllabus was prepared containing definitions, axioms, postulates, constructions, and theorems, grouped around eight main topics. Class sets of two texts were pro-vided and a small library of supplementary .material. Basic concepts were developed through discussion with some teacher demonstration, apparently much l i k e the pattern described by 2 Fawcett i n his classic. Formal proof was approached through exercises and cooperative work with "the instructor prodding and questioning." Formal proof of only 21* out of 133 theorems was required of the students, the remainder being either i n -formally demonstrated or discovered; the ideas were learned but the weight of proof was eliminated In favour of practice and application. Homework "was of a standing variety." Four groups of students were employed i n the Investigation, each under a different teacher; one followed the above plan for a whole year, two others carried on the usual practice with text 1. Fowler, Wynette, An Experiment i n the Teaching of Geometry, . Math. Tch., Feb. 19ij.7: 8I4.-88. 2. Fawcett, H. P., The Nature of Proof, Thirteenth Yearbook, National Council of Teachers of Mathematics. 10 and homework during the f i r s t term but changed to the experi-mental procedure for the second term, and the fourth followed the routine of text and homework over the whole year. A l l groups were tested by standardized plane geometry tests given periodically throughout the year and the results showed sup-erior achievement by those i n the experimental situation. While the multiplicity of variables would seem to render v a l i d conclusions somewhat questionable i n this study, provision for individual differences appears to be inherent i n the experi-mental procedure. Modification of subject matter requirements coupled with the placing of an outline syllabus i n the hands of each student and standing homework could provide for con-siderable differentiation. There even seems to be. some resemblance, although vague, between this procedure and Lee's plan. Through these attempts to provide for student d i f -ferences there appears to be a certain progression of develop-ment. Individual instruction is the dominant i f not the only feature of the early studies but, while i t remains common, it s limitations i n the group situation have become recognized. Homogeneous grouping within classes, with added Instruction for the weak and enrichment for the more able students, i s aided by the grading of exercises on a three-level basis. More recent attempts lean towards provision for greater var-iation i n a b i l i t y and achievement, both i n amount and i n type* with the student participating to some extent i n selection of 11 material, and finding his own level. This plan for meeting individual differences within a single class seems a promising attempt to achieve the advantages of the multiple track plan for groups. Organization of Subject Matter for Heterogeneous Classes The foregoing trends in the teaching of secondary mathematics are by no means unique to that f i e l d but are part and parcel of general developments i n education. They are consistent with a general tendency to adjust a l l subject matter to the needs, a b i l i t i e s , and interests of the student. Such an arrangement for a single heterogeneous class is well illustrated by the "differentiated unit" advocated by Bill e t t , -i n which certain minimum essentials are expected of a l l , but variation i n both amount and type of further activity and achievement is regarded as a natural occurrence to be provided for by f l e x i b i l i t y i n subject matter. Eurell's proposal for heterogeneous classes i n mathematics, that a l l pupils start at the same place but that some proceed further than others, may originally have dealt with only three levels, but applied to a continuum i t could provide the basis for a type of d i f -ferentiated unit. Certain problems suggest themselves, however. What is to be the common starting place? Upon what basis are exer-cises to be graded? Modern psychology has substantiated the 1. B i l l e t t , Roy 0., Fundamentals of Secondary-School Teaching, Cambridge, The Riverside Press, 19lj.O, esp. Chap. XVII. 12 principle of leading from the concrete to the abstract, noted levels of learning, and pointed out that some pupils require longer periods of concrete work and are more limited i n their a b i l i t y to generalise or deal with abstractions* Organization of subject matter In line with this psychological approach now is carried generally from Elementary School arithmetic through Junior High to some of the general mathematics courses of the Senior High School, but l i t t l e change has been made i n the sequential courses which tend to continue at the upper levels i n the traditional style* In this connection Wren1 asks: "How do we know that the traditional sequence and the t r a d i t -ional treatment of subject matter i s the most significant possible In the perspective of problems of modern education?" Perhaps organization and presentation along a progression from the concrete to the abstract, from the practical application to the theoretical background, can provide the common starting place and the basis of gradation even for the material of sequential courses i n the Senior High School* 1. Wren, P. Lynwood, What about the Structure of the Mathe matics Curriculum, Math. Tch., Mch. 19f>l: 166-167* 13 The Inductive vs the Deductive Approach Some studies of this inductive type of approach have been made i n addition to those previously mentioned as attempts to provide for individual differences, Luchins 1 t r i e d building the concept of areas through the use of con-crete materials* proceeding to diagrams, and leading to deductive geometry. He reported a clearer grasp and good retention of the deductive proof as well as proper and wide application of formulas, but this was only a subjective view, 2 Michael, with f i f t e e n classes i n ninth grade algebra, com-pared an inductive method, i n which the class discovered rules through numerous exercises buil t around familiar situations, with a deductive method where the teacher gave rules without reasons followed by extensive practice. He found the deduc-tive group significantly better i n generalizations, but other-wise no evidence to support preference f o r either method. It seems important to note, however, that with the inductive group no attempt was made to state verbally the discovered rules — that these pupils had not had practice i n expressing generalizations. 1, Luchins, A. S. & E, H,, A Structural Approaoh to the Teaching of the Concept of Areas in Intuitive Geometry, Jnl, Ed, Rseh., Mch, 1947: 528-533. 2, Michael, R. E,, The Relative Effectiveness of Two Methods of Teaching Certain Topics i n Ninth Grade Algebra, Math. Tch., Feb. 191+9: 83-87. 111. Ebdes, in a review of experimental studies, has noted that so f a r there is no strong evidenoe in favour of either method. Theoretically, then, the inductive approach offers a basis of progression which.could be used to advantage with heterogeneous classes whose study includes formal mathematics, and the evidence thus far indicates -that no general learning loss would result. But the amount of that evidence is r e l -atively small; the existing total of systematically gathered data concerning pupil achievement under the inductive method as compared with the deductive is insufficient to jus t i f y any conclusion. Moreover, the inductive approach might be sus-pected of emphasizing the concrete, and a loss in comprehen-sion of theory coupled with a gain i n practical achievement could appear as no loss i n general learning. Serious consid-eration should be given, therefore, to the two aspects viewed separately. With the aim of securing further information as to the relative merits of each method, the writer proposes to undertake an experimental study, comparing results under prog-ression from the concrete or the practical application to the underlying theory with those where students proceed i n the traditional style from theorems or rules to applications. 1. Dodes, Irving Allen, The Science of Teaching Mathematics, Math. Tch., Mch. 1953: 159. 15 Summary Secondary school mathematics Is In a state of t r a n s i t i o n . Emphasis on meaning and understanding together with applications to everyday l i f e situations have become well marked trends. "General mathematics," compulsory through the Junior High School, i s organized around these p r i n c i p l e s . In the Senior High School, to a s s i s t i n providing f o r the greatly Increased and v a r i e d population, s o c i a l u t i l i t y mathematics courses have been added to the t r a d i t i o n a l offerings of formal geometry and algebra, and a l l of these made e l e c t i v e . This "double (or multiple) track" can hardly be c a r r i e d on i n small High Schools, however, and i n the large r i n s t i t u t i o n s many students of mediocre a b i l i t y continue to attempt the formal courses. Since heterogeneous groups are common, there i s need f o r some means of applying the multiple track p r i n c i p l e within these single classes; of providing both t h e o r e t i c a l and p r a c t i c a l mathematics with the amount of each va r i e d according to student a b i l i t y . Darellts proposal, that a l l pupils s t a r t at the same place and some proceed further than others, o f f e r s guidance towards organization. Modern psychology and the trend of common practice In the lower grades suggests progression from the concrete or the p r a c t i c a l a p p l i c a t i o n to the abstract or the t h e o r e t i c a l , but the amount of s c i e n t i f i c data concerning the advantages or disadvantages of such an inductive approach i s decidedly l i m i t e d . 16 Statement of the Problem In the Present Investigation Search f o r a means of providing f o r heterogeneous groups has l e d to the question of the r e l a t i v e e f f i c i e n c y of two teaching methods, and the problem f o r in v e s t i g a t i o n i s now stated as follows: General Problem; In the teaching of formal or sequential mathematics i n Senior High School, does an inductive method i n which progression i s from the concrete or p r a c t i c a l a p p l i -cation to the underlying theory (hereinafter r e f e r r e d to as "the inductive method" or Method A) o f f e r advantages over a deductive method i n which progression i s from theory to ap-p l i c a t i o n (hereinafter r e f e r r e d to as "the deductive method" or Method B) when applied to heterogeneous classes? S p e c i f i c Problems: 1. W i l l there be s t a t i s t i c a l l y s i g n i f i c a n t differences between the mean gains i n general learning r e s u l t i n g under Method A as oompared with Method B?„ 2. W i l l there be s t a t i s t i c a l l y s i g n i f i c a n t differences between the mean gains r e s u l t i n g under Method A and Method B: (a) i n the.theoretical aspects? (b) i n the p r a c t i c a l aspects? 3» W i l l there be a higher c o r r e l a t i o n between a b i l i t y and learning gain under Method A than under Method B? CHAPTER II PLAN, SETTING, AND LIMITATIONS OF THE STUDY General Plan In order to Investigate the problem, i t was planned to conduct a controlled experiment using for the sample two equated groups of students, one taught under Method A, the other under Method B. The subject matter, time, and working conditions would be the same for both groups, while the method of presentation would form the variable. Evidence as to the advantages or disadvantages of the Inductive method would be sought i n comparison both of the learning gains i n general and of the theoretical and the practical aspects considered separately. Since the problem concerned a specific type of situation, i t was planned to draw the sample from a common heterogeneous population and the subject matter from the normal material i n a sequential type course. Setting for the Experiment Two classes i n the same mathematics course were being taught by the writer at Kamloops, Bri t i s h Columbia. This course, known as Mathematics 30 i n the Brit i s h Columbia Programme of Studies, formed the second year»s work on the sequential line of a double track program and was compulsory for students seeking entrance to university i n the province. It contained selected topics i n geometry and algebra, graphs, elementary trigonometry, and logarithms. Although 18 considerable stress was placed upon applications and upon c r i t i c a l thinking, i n l i n e with modern trends, organization of the subject matter tended to remain t r a d i t i o n a l i n s t y l e with the deductive approach generally dominant, 1 One of these classes contained 17 g i r l s and 10 boys of approximately 16 to 18 years of age whose I.Q.'s ranged from 90 to 125, the other had 16 g i r l s and 10 boys s i m i l a r l y aged from 16 to 18 years with i . f t , f a from 93 to 125. These were i n a Junior-Senior High School of composite type having a t o t a l enrolment of about 900 p u p i l s . In the senior grades this school provided a v a r i e t y of academic courses including some s p e c i a l i z a t i o n i n languages, science, mathematics, and s o c i a l studies. It also offered a f a i r program In commercial subjects, home economics, i n d u s t r i a l a r t s , music, and a r t . The majority of the students i n the two mathematics classes were attempting u n i v e r s i t y entrance but, as there was a considerable d i v e r s i t y of courses within the entrance program, no common pattern predominated among the members of either group. The community served by the school Is a r a p i d l y growing c i t y and suburban v i l l a g e of close to 10,000 people, and the surrounding country within a radius of approximately 30 miles. One-third or more of the pupils are transported by school bus. The c i t y i s a r a i l r o a d d i v i s i o n a l point and a 1. B r i t i s h Columbia Department of Education, Div i s i o n of Curriculum, Mathematics 1950» 19 commercial d i s t r i b u t i o n centre f o r a wide area; i t also has resident a large number of government service employees. In the surrounding country served d i r e c t l y by the school, intensive f r u i t and vegetable growing, c a t t l e ranching, and lumbering are industries of considerable importance. Perhaps one-quarter of the adults i n the school d i s t r i c t are of for e i g n b i r t h . Thus, the occupations of the parents and the s o c i a l and economic backgrounds of the pupils v a r i e d consider-ably and this d i v e r s i t y was common through both mathematics classes. In t h i s s i t u a t i o n , the two classes i n a sequential course, s i m i l a r l y heterogeneous as to background and a b i l i t y , appeared to s a t i s f y reasonably well the requirements of the plan f o r a sample, and they were selected f o r the experiment. Design of the Experimental Study Examination of the two classes revealed that matched pairs were not obtainable i n any quantity, and i t was decided to equate the groups by mean and standard deviation on the bases of both and previous achievement i n mathematics. To compensate f o r the smallness of the sample, i t was planned to attempt a series of short experiments as the equivalent of several pairs of groups. Here an opportunity arose to strengthen conditions f o r equality of factors other than the var i a b l e , and the experimental design now was structured so as to alternate the two methods with each c l a s s . 20 The idea of conducting the experiment i n several schools was considered* While this would provide a larger sample, the conditions of the experiment would be much more d i f f i c u l t to control* The plan was not discarded, however, but l e f t i n abeyance as a possible addition later* The short unit experiments allowed for more r i g i d control of working conditions* Originally four of these were considered but, because the length of time i n operation would reintroduce problems of control and because preparation of four complete sets of exercises and tests would be necessary, the f i n a l plan employed only two units* Subject Matter From the material regularly prescribed for the Mathematics 30 course two sections were chosen: one on elementary trigonometry dealing with the theory of simple trigonometric ratios and their application to indirect measurement, the other on plane geometry dealing with both theoretical and practical calculation aspects of chords i n a c i r c l e * While this material was selected a r b i t r a r i l y , an attempt was made to choose portions of the course that would lend themselves to inductive treatment neither more nor less readily than others* 21 Measurement and Comparison Since the experiment was designed as a series of short units with al t e r n a t i o n of method between the two groups, i t was planned to measure the learning gains by u n i t t e s t s . The mean and standard deviation would be employed, and comparisons of the unit means under each method viewed over the whole s e r i e s . Limitations of the Study This study seeks evidence as to whether the inductive method offers advantages over the deductive method. The general problem r e s t r i c t s i t s scope to the teaching of sequential mathematics i n heterogeneous classes of the Senior High School. The sample groups appear heterogeneous, and s t a t i s t i c a l procedures w i l l determine the extent to which t h e i r results may be applicable to a large population, yet these procedures can not e s t a b l i s h that such population i s the great mass of Senior High School students i n sequential mathematics classes* The subject matter f o r the experiment consists of two units from a s p e c i f i c course and, as both course and units were chosen subjectively, i t may or may not be t r u l y representative of a l l formal or sequential mathematics. Any conclusions drawn from t h i s experiment, therefore, must be applied cautiously to the teaching of mathematics generally or even to heterogeneous classes and sequential mathematics In general. Yet re s u l t s may be viewed 22 together with those from other objective studies as b i t s evidence contributing to knowledge of a general p i c t u r e . CHAPTER I I I PROCEDURE Since method was to constitute the single variable* the plan required that subject matter, time, and working conditions should be equalized under r i g i d c o n t r o l . Preparation of Material To ensure that subject matter would be a constant, a d e f i n i t e s e l e c t i o n was made at the beginning from the content prescribed f o r each u n i t . This material was then divided into lesson sections, each containing b a s i c a l l y e i t h e r t h e o r e t i c a l or p r a c t i c a l work. Generally one section f i t t e d a single class period of f o r t y minutes, but some required two periods. The aim of t h i s d i v i s i o n was to provide that the time devoted to each type of material as well as the t o t a l time would be the same f o r each group; i t also paved the way f o r the next step. Order of presentation formed a main feature of the difference i n method. Accordingly, the lesson sections were arranged i n two sequences, one f o r Method A had p r a c t i c a l exercises f i r s t and theory l a s t , the other f o r Method B had the same material i n reverse order. For example, i n the f i r s t u nit Sequence A began with i n d i r e c t measurement of r e a l objects while the f i r s t lesson of Sequence B dealt with the theory of trigonometric r a t i o s . > The l a t t e r material occurs i n Sequence A, however, i n Lesson Outlines of both 2k sequences showing the general subject matter content are given i n Tables I and I I . TABLE I Outline of Lesson Sequences - Elementary Trigonometry Unit Sequence A Lesson No. Subjeot Matter Sequence B Lesson No. 1 Indirect measurement of r e a l objects using tangent 6 2 Indirect measurement using s i n & cos 7 3 & k Calculation problems as above but from given data k & 5 5 Theory - r a t i o s constant f o r same angle 1 6 Theory - r a t i o s vary as angle changes 2 7 Construction of angle from given function 3 25 TABLE II Outline of Lesson Sequences - Chords i n a Circle Unit Sequence A Lesson No, Subject Matter Sequence B Lesson No, 1 & 2 Calculation exercises - chord, distance from centre, and radius 5 & 6 3 Construction exercises - c i r c l e through three points, etc. k k Two theorems on chord and perpendicular 1 5 &-6 Third theorem and theoretical exercises 2 & 3 The individual lessons then were organized for presentation. Those for each sequence were prepared separate-l y since method, the variable, frequently required differences in explanation of the same subject matter to accord with the order of presentation. As a means of control over the teacher factor, explanations and work for each lesson were set down In specific detail, and to guard against departure from the pattern during class operation, the material as f i n a l l y arranged was mimeographed for distribution to students; these lesson sheets formed a combination text and work-book. Three lessons from the f i r s t unit are given on the next pages for i l l u s t r a t i o n . Comparison of Lesson 1 of Sequence A with Lesson 1 of Sequence B shows the difference in approach between the two methods. Comparison of the latter Elementary Trigonometry Unit. Group Period 1. Introduction; Certain dimensions which are difficult or impossible to measure directly, such as the height of a tree, a building, or a room, can often be calcul-ated i f we can measure one related distance find one related angle. Demonstration Example; (The working of this will be shown by the teacher, one step at a time, with students following and carrying out the operations step by step). Fhat is the height of this classroom? Using a- sighting protractor an^ level placed on a desk, sight the intersection of wall and ceiling and read the angle of elevation. Mea-sure the distance along the floor from point under the observer's eye tb the vertical wall. Record these t^o measurements; Ahgle of elevation j horizontal distance Make a dia-gram in the space at the right; mark the angle, base distance, anr' unknown to be found on i t . In a? right-angled triangle, the ratio of vertical side to base is called the tangent of the lower angle; we can find the value of this from a table on page 512 of the text-book. t" rite: tangent of ° is We then write an equation = and solve i t Table Practice; Find tangent of 7°; 16°; 30°; 53°; 72°; 80°. Practice Exercises; Students work in pairs; sight angle and measure distance together but each work out calculations and check result with erech other. 1. Find height of a teee immediately outside school. 2. Find height of s pole » » " 3. Find height of school building. 4. Find height of any -joint on classroom wall (in case weather does not allow 5. Find height of electric light in classr~>om. outside work) Elementary Trigonometry Unit. (GROUP B*) SEQUe/t/cF B Period 1. Introduction; Recently we proved the theorem: "tf two triangles are equiangular their corresponding sides are proportional. n The ratios of sides of equiangular right-angled triangles are of great importance in mathematics and are widely used. Exercises; The following are to be read and worked or completed by each student. As'these are demonstration and study examples1, explanations will be given and re-sults checked as the work proceeds". 1. BAC and EDF, shown immediately below^ are equiangular right-angled triangles Complete: (i) BC _ (ii) AC ^ AB ~ ( i i i ) BC AXT ~ 2. Construct a right-angled triangle lettered like the sample BAC ajpove but having sides: a> » 3 cm; b » 4 cm. (Use the left side space below) With protractor, measure angle A and write its^ sixer here degrees. Calculate the length of side^"c n (Pythagoras theorem) j check by measuring. Write in figures, f i r s t as common fractions, then as decimals, the ratios: (i) a? _ = . (ii) b = _. ( i i i ) a m . c c b 3. In the right hand space-above} construct another right-angled triangle, lettered the same, but having side- "bj1 6 cm; maker angle: A" the same size as in No. 2 by using your protractor. Measure^ the other two sides after the triangle is drawn and write the ratios", f i r s t as common fractions, then as decimals: (i) a _ a * (ii) b _ _ 3 . ( i i i ) a _ _ . c dr b Since angle A remained constant, would you expect these ratios to be the same for both triangles? 4. If side b is 10 f t . and angle A the same, calculate side a 5. If side c is thirty miles and angle A the same, calculate- sides a and b Definitions: Because, triangles can be lettered in many ways, a- standard means of naming sides has been adopted to avoid confusion. One of the acute angles is taken as a reference point and the sides are spoken of as-: the hypotenuse the side opposite to the angle the side adjacent to the angle The ratios have been given the following names: S l d e "SStSuS i S C a l l e * *** <*»> of the angle. side adjacent to angle i 8 ; o m l l e d COSINE (Cosln; Cos) of the angle, hypotenuse side opposite-to angle i j r o a l l e d TANGWT (Tan) of the angle, side adjacent to angle Exercise: Identify the ratios Sin A, Cos A% and Tan A' of No* 2 above1. ' Cheek their values with those given for angle A in tables at back of text-book. Elementary Trigonometry Unit. (Group £j] Sequence A Period 5. t^tiat are'-these ratios: Sine, Cosine, and Tangent? A standard method of naming the sides of right angler) triangles has been adopter!. One of the acute angles is taken as a reference point and the sides are called: the hypotenuse the side opposite to the angle the side adjacent to the angle The SINE (Sin) of the angle is alrays side opposite to angle hypotenuse The COSINE (Cosin, Cos7) of the angle is always' side- adjacent to angle hypotenuse The TANGENT (Tan) of the angle is always- side opposite to angle side adjacent to angle What happens to these ratios when triangles differ in length of sides but angles remain constant? In the figures immediately below, BA(T and E7?D are equiangular right-angled t r i -angles? side BC'is 5 cm., side ACT is 4 cm., side- ED iff 4-| cm., side AD is 6 cm. t p ct O » M H H o et ca o S3 VA % CO ® g to 00 A C A (In the exercises below, the length of the hypotenuse may be found by calculation of measurement 1. Write: tangent of angle A is s?4e" ~ side -For triangle BAC, tangent R = F o r triangle EAD, tangent A = 2. Write: sine of angle A is side For triangle BAC, sine A =* F o r triangle EAD, sine A = 5. Write: cosine of angle A is s i d e "  For triangle BA'C, cosin R - p 0r triangle EAD, cos A = ^  4. Reduce- each of the above-ratios to its lowest terms and complete this statement: If an angle remains-' constant then the sd.no> cosine", and tangent each  no matter how large the-triangle. 5. Reduce" each of the above1 ratios tb a decimalj Sin A" Cbs A Tan A 6. Measure angle A with protractor, find its sin, cos, and tan from tables and check your values of No. 5. 7. Measure angle B (note that A + B must total 90°) and find from table the values of sin B , cos B and tan B 8. From the triangle BACT above write the values of sin B, cos- B, and tan B from the lengths of the sides7; Reduce each to decimal and compare with No. 7. 29 with Lesson 5 of Sequence A Indicates the difference i n treatment of the same subject matter* A copy of the mimeo-graphed d e t a i l f o r a l l lessons i s attached as Appendix A. Classroom Procedure As a further control of the time f a c t o r , a l l work during the experiment was confined to the regular class periods, no homework being assigned* The mimeographed sheet f o r the lesson was d i s t r i b u t e d at the beginning of each period together with a l l previous pages but none i n advance* Students 1 work was written on these sheets or on foolscap and a l l papers were taken from them at the end of the period to be returned on the following day* Since these features of the procedure were f o r e i g n to normal routine and the students would r e a l i z e that some unusual type of te s t was occurring, i t was f e l t that a more stable s i t u a t i o n would p r e v a i l i f they were taken into confidence* Accordingly, both groups were informed that a s p e c i a l piece of work was to be conducted which required no homework, that the course was being tested rather than them-selves, and that they could contribute to the success of the project by working as normally as possible* The lessons of the f i r s t u n i t occupied seven ordinary class periods and those of the second unit six* In each case one additional period was taken f o r review, and the f i n a l t e s t was administered on the following day* 30 Measurement Teacher-made tests were used to measure r e s u l t s . For the unit on elementary trigonometry, the subject matter was considered to be e n t i r e l y new material hence only a f i n a l t est was given and the marks on t h i s were treated as gain. Items of t h i s test were balanced between p r a c t i c a l and theor-e t i c a l types of work so as to provide a basis f o r considering the question of whether Method A would r e s u l t i n higher prac-t i c a l achievement at the expense of the t h e o r e t i c a l . The unit on chords i n a c i r c l e included material previously covered so both a pretest and a f i n a l test were employed here. In constructing these, pairs of s i m i l a r Items were made ready and one of each p a i r a l l o t t e d to the pretest or to the f i n a l test by tossing a coin. Learning gain was measured as the difference between the f i n a l and pretest marks of each student. An attempt was made to balance these tests between t h e o r e t i c a l and p r a c t i c a l but was abandoned as un-sa t i s f a c t o r y . However, a t h e o r e t i c a l proof was added to the f i n a l t e s t . A copy of each of the three tests i s attached as Appendix B. Administration The f i r s t part of the experiment was conducted at Kamloops early i n 195>2 with Group A taught under Method A and Group B under Method B. For the second un i t , c a r r i e d on about s i x weeks l a t e r , the planned reversal was made; Method A was 31 used f o r Group B and Method B f o r Group A. Both classes met i n the mornings, one immediately a f t e r the other, and a l l periods were f o r t y minutes i n length. Individual attendance was recorded throughout so that absentees might be eliminated as subjects or, as an a l t e r n a t i v e , the groups equalized i n th i s respect. Before class work was begun an i n t e l l i g e n c e t e s t , the Otis Quick-Scoring Gamma, was given to a l l students. Groups were equated by mean and standard deviation using both I.Q. and f i r s t term achievement In mathematics. Pour students who were repeating the course as well as two c h r o n i c a l l y i r r e g u l a r attendants were not considered, and two transfers were made to secure a better balance. This gave prospective groups f o r the sample as shown i n Table I I I . 1 TABLE III Preliminary Equating of Kamloops Groups • Number I.'Q. 1st Term Marks i n Group Mean S.D. Mean S.D. Group A 23 110.0 8.k 66.6 11}-. 5 Group B 23 109.0 8.5 66.9 12 .8 32 F i n a l s e l e c t i o n of personnel was postponed, however, u n t i l the record of attendance had become available* It was then found that exclusion of a l l absentees, while i d e a l , would greatly reduce the size of the sample and seriously disturb the balance between the groups* Yet students having any appreciable number of absences could hardly be considered as participants* In a rather a r b i t r a r i l y determined compromise, a l l those absent f o r any tes t or during more than two periods of e i t h e r unit were eliminated, and two others dropped i n equating* The r e s u l t of t h i s procedure i s shown i n Table IV i n the next chapter* In November of the same year, the work of the f i r s t unit was repeated with classes at Chilliwack and at Langley i n the lower Fraser Va l l e y of B r i t i s h Columbia* This area i s a r i c h delta where dairying and the growing and processing of small f r u i t s and vegetables are basic industries* A f a i r amount of lumbering also Is c a r r i e d on* Both towns are commercial centres, and each has a large composite High School with approximately h a l f the pupils urban resident and the others conveyed by bus from r u r a l t e r r i t o r y * In each of these schools the experimental work was conducted by the regular teacher of two groups who used the two sequences of mimeographed lesson sheets and the achieve-ment t e s t under the d i r e c t i o n of the writer. As available mathematics marks f o r the previous year were i n l e t t e r grade form, equating was possible only on the basis of I.Q.'s as 33 regularly obtained and used In each school* At Chilliwack, Group A o r i g i n a l l y contained 3k pupils and Group B 38* each i n one class* In several cases I.Q.'s were unavailable; these pupils were eliminated along with absentees, and two were dropped i n equating* The r e s u l t i n g groups are shown i n Table V of the next chapter* In t h i s school, because 55 minute periods were customary, the f i n a l review period was omitted. At Langley, two small classes of Ik and 15 pupils .respectively were considered Group A, while Group B had 33 pupils i n one class* Eliminations as before gave equated groups as shown i n Table VI of the next chapter* Here the seven kO minute periods plus one f o r review were employed* CHAPTER IV ANALYSIS OP RESULTS Equality of Croups Each p a i r of groups was equated by the mean and standard deviation of I.Q.'s. Those at Kamloops were equated also on the basis of mathematics marks f o r the previous term, the mean and standard deviation again being employed. Table IV shows a comparison of the two Kamloops groups as f i n a l l y equated. TABLE IV P i n a l Equating of Kamloops Groups Number i n Group Boys G i r l s Total I. Mean S.D. 1st Term Marks Mean S.D. Group A Group B 7 11 18 6 12 18 109.3 109.2 8.8 8.7 68.5 69.1 13.9 11.1 The difference between the means f o r I.Q. i s 0.1, and f o r f i r s t term marks 0.6. In the l a t t e r case the standard error of the difference has been computed as lj.»3» using the formula SEt, t^** J /V' ^  $ and the c r i t i c a l r a t i o , t b M ' " ^ Z , as O.llj.. The difference i s not s i g n i f i c a n t 5 k p s t a t i s t i c a l l y . Calculations are shown i n Appendix C. 35 A comparison of the Chilliwack groups Is shown In Table V, and of the Langley groups i n Table VI. TABLE V Equating of Chilliwack Groups Number i n Group Mean I.Q. S.D. I.Q. Group A 25 110.2 10.7 Group B 32 108.k 10.3 The difference between these means Is 1.8. The standard error of the difference and the c r i t i c a l r a t i o have been computed as before at 2.88 and O.63 respectively. The difference i s not s i g n i f i c a n t s t a t i s t i c a l l y . TABLE VI Equating of Langley Groups Number i n Group Mean I.Q. S.D. I.Q. Group A 22 108.0 9.1+ Group B 28 108.0 10.9 There i s no difference between the cal c u l a t e d means. Group A, however, was composed of two small classes whereas Group B was a single c l a s s . 36 General Achievement of Groups The learning gains of students taught under both methods were measured by the teacher-made tests previously described i n Chapter I I I , Comparison i s made by the mean and standard deviation of the raw t e s t soores f o r each group* For Unit I these are the f i n a l t e s t marks while f o r Unit II the difference between the f i n a l and the pretest marks has been taken f o r each student* For each p a i r of groups the standard error of the difference between means and the c r i t i c a l r a t i o " t " have been calculated using the formulas previously given on page 3k» i n order to determine the sign i f i c a n c e of any difference, (N - 1) degrees of freedom f o r the combined sample have been considered i n each case* The general achievement of the Kamloops groups i s shown i n Tables VII and VIII. TABLE VII General Achievement of Kamloops Groups i n Unit I Number i n Group Mean Test Score "S.B. Group A 18 22.9 Group B 18 22.3 k.k The difference between the two means i s 0*6* The standard error of the difference i s 1.5 and the c r i t i c a l r a t i o 37 i s G-.ij.C-. For N - 1 B 35 degrees of freedom the difference i s not s i g n i f i c a n t s t a t i s t i c a l l y . TABLE VIII General Achievement of Kamloops Groups i n Unit I I Number F i n a l Test Pretest Gain i n Group Mean S.D. Mean S.D. Mean S.D. Group A 18 27 ?3 5.6 6.8 M 20.5 5.3 Group B 18 27.9 5.0 8.2 5.9 19.7 5.2 The difference In mean gains and also those between the means of f i n a l test and pretest scores are shown, together with the standard error and c r i t i c a l r a t i o f o r each,in Table IX. TABLE IX Test and Gain Differences - Unit II F i n a l Test Pretest Gain Difference i n Means 0.6 l . l j . 0.8 S.E. Difference 1.8 1.8 1.8 C r i t i c a l Ratio 0.33 0.78 O.I44 No difference above i s s i g n i f i c a n t s t a t i s t i c a l l y . 38 Tables X and XI show the general achievement of the Chllliwack and Langley groups i n Unit I. TABLE X General Achievement of Chilliwack Groups i n Unit I Number i n Group Mean Test Score S.D. Group A 26.1* Z.k Group B 32 26.6. • 2.0 The difference In means is 0.2, the standard error of the difference 0.59, and the c r i t i c a l ratio 0.31+. N - 1 for the combined sample is £6. The difference Is not significant s t a t i s t i c a l l y . TABLE XI General Achievement of Langley Groups In Unit I Number i n Group Mean Test Score S.D. Group A 22 21*.6 3.1 Group B 28 23.6 - 3.9 The difference i n means is 1.0, the standard error l.Ol*, and the c r i t i c a l ratio 0.96. N - 1 is lj.9. The difference is not significant s t a t i s t i c a l l y . 39 The f o r e g o i n g data on mean gains i n general l e a r n i n g are summarized i n Table X I I . TABLE X I I Comparison of Mean Gains i n General Learning Kamloops Kamloops C h i l l i w a c k Langley Unit I Unit I I Unit I unit I Method A, Mean 22.9 19.7 26.1+ 21+.6 Method B, Mean 22.3 20.5 26.6 23.6 D i f f e r e n c e (A - B) / 0.6 - 0.8 - 0.2 / 1.0 S.E. Difference 1.1+6 1.79 0.59 1.01+ C r i t i c a l R a t i o 0.1+0 o.kk 0.31+ ' 0.96 Degrees of Freedom 35 35 56 k9 S i g n i f i c a n c e n i l n i l n i l n i l Achievement i n P r a c t i c a l and i n T h e o r e t i c a l Work The attempt t o measure l e a r n i n g gains i n p r a c t i c a l and i n t h e o r e t i c a l work s e p a r a t e l y was confined to Unit I as the Unit I I t e s t s were considered u n s a t i s f a c t o r y f o r t h i s purpose. Because of f a u l t y communication w i t h the other two schools, r e s u l t s became a v a i l a b l e f o r the Kamloops groups only. These r e s u l t s are shown i n Table X I I I . TABLE XIII Results i n Theoretical and P r a c t i c a l Work Shown Separately Theoretical Mean S. D. P r a c t i c a l Mean S.D. Method A 6.3 2.1* Method B 6.I4. 2.7 Difference (A - B) - 0.1 8.3 8.1 / 0.2 1,8 1.1* As the differences between means f o r the two methods appear n e g l i g i b l e i n each case, no calculations of standard error and c r i t i c a l r a t i o have been made. For either method, however, the mean score on p r a c t i c a l Items was larger than that on t h e o r e t i c a l items. A summary of these differences i s shown i n Table XIV. TABLE XIV Mean Score Differences Between P r a c t i c a l and Theoretical Method A Method B Mean Score - P r a c t i c a l 8.3 8.1 Mean Score - Theoretical 6.3 6.1* Difference (Prae, - Theor.) 2.0 1.7 S.E. Difference 0.714- 0.71+ C r i t i c a l Ratio 2.70 2.30 Level of Significance •ei .05 kl Correlation Between A b i l i t y and Achievement Coefficients of c o r r e l a t i o n between I.(£. and learn -ing gain under each method as measured by test scores have £ 1 been computed using the formula r s . . . Those which include general or t o t a l learning gain are shown i n Table XV, TABLE XV Correlation Between I.Q. and Test Score Gain Unit I Kamloops Chilliwack Langley Unit II Kamloops Number i n Group Method A Method B 18 22 18 18 32 28 18 Corr. C o e f f i c i e n t Method A Method B .63 .19 •13 .06 .55 .17 .13 .Ik Use of the c r i t i c a l r a t i o , t Z •{<vj'/ ._— , shows that f o r N - 2 degrees of freedom the c o e f f i c i e n t s of .63 and .55 are s i g n i f i c a n t at the .02 l e v e l while the others have no s t a t i s t i c a l s i g n i f i c a n c e . It should be noted, however, that 1. This formula was used because the components were already available from previous c a l c u l a t i o n s . 1*2 Kamloops I.Q. «s were from one recent test but that the o r i g i n of the others i s not d e f i n i t e l y known. Also that Unit I scores were from one f i n a l test while Unit II scores were the differences between marks on two t e s t s . C o e f f i c i e n t s have been computed also of c o r r e l a t i o n between I,Q, and achievement In the t h e o r e t i c a l aspects, and between I.Q. and achievement i n the p r a c t i c a l aspects of the work of Uhit I as evidenced by test marks f o r the Kamloops groups. These are shown i n Table XVI, TABLE XVI Correlation Between I.Q, and Test Marks P r a c t i c a l and Theoretical - Unit I - Kamloops Groups Number i n Group Corr, C o e f f i c i e n t Method A Method B Method A Method B I.Q. - Theor, 18 18 .54 *k$ i . a . - P r a c t i c a l 18 18 .37 .35 Use of the c r i t i c a l r a t i o as before shows that f o r N - 2 degrees of freedom the c o e f f i c i e n t of .54 i s s i g n i f i c a n t at the .02 l e v e l and that of .1+5 at the .10 l e v e l . CHAPTER V SUMMARY AND CONCLUSIONS Summary of the Problem and Its Background This study considers an inductive approach to the sequential mathematics of the Senior High School as a method whereby better provision may be made f o r the differences i n a b i l i t y and Interests of students In heterogeneous classes. The secondary school of to-day attempts to serve a greatly increased and varie d population and to thi s end offers as d i v e r s i f i e d a program as f a c i l i t i e s w i l l permit. In the mathematics; of the higher grades the double or multiple track system provides formal mathematics f o r some pupils and vocational or s o c i a l u t i l i t y arithmetic f o r others. But, since these are organized i n separate courses, the system appears l i m i t e d to the lar g e r High Schools and i t s success In these dependent on adequate guidance. In the many small High Schools and to a considerable extent i n the larger ones heterogeneous classes are common, and the means of providing f o r i n d i v i d u a l differences within these groups remains a problem. Modern psychology and the trend of common practice i n lower grades suggests that a l l pupils i n such classes might st a r t together with p r a c t i c a l applications and each progress as f a r into t h e o r e t i c a l work as he i s able. But a long h e l d view concerning the l o g i c a l sequence of formal mathematics seems to c o n f l i c t with t h i s idea, hence i t i s necessary to kk consider whether or not such an inductive approach would r e s u l t e i t h e r i n loss of learning generally or i n loss of achievement i n the t h e o r e t i c a l aspects of mathematics. Studies made thus f a r comparing the inductive and deductive methods of teaching mathematics indicate l i t t l e preference f o r either , but the amount of such research i s l i m i t e d . In an attempt to add to e x i s t i n g knowledge a con t r o l l e d experiment was undertaken, based on the problem stated as follows: General Problem: In the teaching of formal or sequential mathematics i n Senior High School, does an inductive method i n which progression i s from the concrete or p r a c t i c a l a p p l i -cation to the underlying theory (hereinafter r e f e r r e d to as "the inductive method" or Method A) o f f e r advantages over a deductive method i n which progression i s from theory to ap-p l i c a t i o n (hereinafter r e f e r r e d to as "the deductive method" or Method B) when applied to heterogeneous classes? S p e c i f i c Problems: 1, W i l l there be s t a t i s t i c a l l y s i g n i f i c a n t differences between the mean gains i n general learning r e s u l t i n g under Method A as compared with Method B? 2. W i l l there be s t a t i s t i c a l l y s i g n i f i c a n t differences between the mean gains r e s u l t i n g under Method A and Method B: (a) i n the t h e o r e t i c a l aspects? (b) i n the p r a c t i c a l aspects? 3 . W i l l there be a higher c o r r e l a t i o n between a b i l i t y and learning gain under Method A than under Method B? The Experiment The project was designed i n the form of a series of short unit experiments i n each of which two equated groups would carry on a section of t h e i r regular mathematics course, one of these classes being taught by Method A and the other by Method B. The method was to be alternated between the groups f o r succeeding u n i t s . A series of two units, each occupying eight lj.0 min-ute periods, was c a r r i e d out with sample groups at Kamloops, B. C. Later the f i r s t unit was repeated with two classes at Chilliwack and with two others at Langley i n the same province. The subject matter consisted of two sections from a course i n the B. C. curriculum designated Mathematics 3 0 , i n which a l l students p a r t i c i p a t i n g had enrolled. The material selected f o r each unit was; f i r s t divided into a d e f i n i t e number of lessons which then were organized i n two sequences according to method. Subject matter, time, and to some extent emphasis upon each type of work were thus c o n t r o l l e d as constants. Elimination of homework also aided i n control of time. Additional r e s t r a i n t of emphasis upon either type of work and regulation of the teacher f a c t o r were provided by mimeographing the complete d e t a i l and presenting i t to the classes lesson by lesson. 1*6 Equality of Groups Kamloops groups were equated by the mean and stand-ard deviation on the bases of previous marks In mathematics and of I.Q.'s obtained from a standardized test given shortly before the experimental work began* The others were equated only on the basis of I.Q.. 's as on f i l e i n t h e i r respective schools. In a l l oases the difference between the means was s l i g h t and not s i g n i f i c a n t s t a t i s t i c a l l y as shown i n Tables IV, v, and VI. In each group there was a considerable range and a sizable deviation i n d i c a t i n g that i t was heterogeneous as to a b i l i t y . Economic and s o c i a l background of students appeared to be s i m i l a r l y heterogeneous. In general i t may be f a i r l y claimed that i n each of the three samples the groups were well equated but, because of v a r i a t i o n i n the means of obtaining I.Q.'s ?there i s some question about combining the three pairs into a single sample of two groups. Measurement A l l tests employed to measure learning gains were constructed by the author. For Unit I only a f i n a l t e s t was used, as trigonometry was e n t i r e l y new to the students, and t h i s t e s t contained sections on theory and on p r a c t i c a l work of equal score value. For the plane geometry of Unit I I , however, the difference between a f i n a l t e s t and a pretest formed the score counted as gain. An attempt i n these to measure theory and p r a c t i c a l work separately was abandoned. Summary of Results Results of the experiment stated as direct answers to the specific questions of the problem are as follows: 1, There were no s t a t i s t i c a l l y significant differences between the mean gains i n general learning resulting under Method A as compared with Method B. 2, There were no s t a t i s t i c a l l y significant differences between the mean gains resulting under Method A and Method B i n either the theoretical or the practical aspects, (Information here came from one sample only), 3, In one case the correlation between and test score gain under Method A was slightly higher than that under Method B, In the other three eases a l l coefficients were negligible. Two additional results were obtained from a single pair of groups, information on the same features not being available from the others. These results, numbered with reference to those above, are as follows: 2A, Under both methods the scores for practical work were significantly higher than those for theoretical work, 3A, The coefficients of correlation between I.Q, and scores i n theoretical work were higher than those between I.Q, and scores i n practical work, with some significance, and of the former, that for Method A was slightly higher than that for Method B, 1*8 Interpretation of Results On the question of advantage i n general learning, the results of t h i s experiment do not favour either method. This f i n d i n g i s In accord with that of Michael. 1 I t d i f f e r s p from views favouring the Inductive method by Luchins and by McCreery^ but these were only subjective opinions. In t h i s connection i t i s worthy of note that at l e a s t two teachers who p a r t i c i p a t e d i n the experiment likewise expressed preference f o r the inductive approach, yet the mean test scores of t h e i r classes did not show s i g n i f i c a n t differences. To r e f e r back to Bodes' summary,^" there i s s t i l l no strong evidence i n favour of either method. But the f a c t that s i g n i f i c a n t differences did not appear i s not to be accepted as conclusive evidence that there were none. It Is possible that differences i n learning gain existed which the tests f a i l e d to detect, or that differences due to method were counteracted by other f a c t o r s . 1. Michael, op. c i t . (See page 13). 2. Luchins, op. c i t . (See page 13)* 3. McCreery, Gene S., Mathematics f o r A l l the Students i n High School, Math. Tch., Nov. 191*8: 302-308. 1*. Dodes, op. c i t . (See page l l * ) . 1+9 In this experiment the results were from three small but well equated samples. The amount of subject matter was l i m i t e d . Time and working conditions were reasonably weir controlled. But the v a l i d i t y of the tests from which r e s u l t s were obtained i s open to some question. However, i n the case of one sample where I.Q.fs were taken from a standardized t e s t , recently administered, the r e l a t i v e l y high c o r r e l a t i o n between I.Q, and test scores gives some support to the v a l i d i t y of the l a t t e r . This may appear to be contradicted by the low coef-f i c i e n t s i n the other cases, but due to circumstances already noted these can not be given as much weight, 1 Taking a l l factors into consideration, the writer concludes that, with respect to advantage i n general learning between the two methods, the results of t h i s experiment give a d e f i n i t e i n d i c a t i o n i n favour of the n u l l hypothesis. The question of differences In learning gain i n the t h e o r e t i c a l and the p r a c t i c a l aspects considered separately was o r i g i n a l l y r a i s e d because of a seeming p o s s i b i l i t y that the inductive method might emphasize the l a t t e r at the expense of the former. No such disadvantage f o r the Inductive method i s indicated from th i s experiment, although once again the f a c t that differences were not s i g n i f i c a n t s t a t i s t i c a l l y does not c e r t i f y that there were none. The higher c o r r e l a t i o n of I.Q. to t h e o r e t i c a l than to p r a c t i c a l , shown In Table XVI, 1, See Table XV and following comment; also pages 31-33. 50 coupled with the s i g n i f i c a n t and r e l a t i v e l y high c o e f f i c i e n t s between I.Q. and t o t a l score by the same sample, lends some reinforcement to the d i s t i n c t i o n made subjectively by the writer i n composing the t e s t , since I.Q. Is accepted as our best present measure of a b i l i t y i n handling abstractions. But the test items covering each aspect of the work were few i n number. Moreover, re s u l t s were available only f o r one of the.three samples. The writer concludes that from incomplete measure-ment there i s no evidence of learning loss i n the t h e o r e t i c a l aspects under the inductive method. This conclusion Is at variance with that of. Michael'1' who found the deductive group s i g n i f i c a n t l y better i n generalizations. The questionable v a l i d i t y of the test and the p e c u l i a r i t y of the single source of information a f f e c t also any Interpretation to be placed on the r e s u l t that under both methods the mean scores f o r p r a c t i c a l work were s i g n i f i c a n t l y 2 higher than those f o r t h e o r e t i c a l work. Subject to t h i s q u a l i f i c a t i o n , the writer would conclude that the p r a c t i c a l or more concrete aspects form an area of^ better achievement f o r heterogeneous classes. Prom the viewpoint of modern psychology that success causes s a t i s f a c t i o n and encouragement to proceed, t h i s suggests a possible advantage f o r the inductive method. 1. Michael, op. c i t . 2. See Table XIV. 51 The t h i r d s p e c i f i c question of the problem dealt with correlations between I.Q. and test score gain under each method. By comparison of these i t was sought to discover whether greater e f f i c i e n c y i n matching achievement to a b i l i t y would occur under the inductive method than under the deductive. The r e s u l t i n g c o r r e l a t i o n c o e f f i c i e n t s , shown i n Table XV, have already been discussed. Prom such c o n f l i c t i n g r esults no conclusion can be drawn. Summary of Conclusions 1. The r e s u l t s of t h i s experiment show neither advantage nor disadvantage i n general learning f o r the Inductive method as compared with the deductive. There i s a d e f i n i t e i n d i c a t i o n i n favour of the n u l l hypothesis. 2. Prom incomplete measurement there i s no evidence of advantage i n the t h e o r e t i c a l aspects under either method. 3. Prom incomplete measurement there i s an i n d i c a t i o n that the p r a c t i c a l aspects form an area of better achievement f o r heterogeneous classes. !+• Because of c o n f l i c t i n g evidence no conclusion can be drawn as to whether either method results i n a higher c o r r e l a t i o n between a b i l i t y and achievement. 52 C r i t i c a l Note and Suggestions Tor Further Study The experiment described herein was undertaken to secure, information on the r e l a t i v e merits of two methods of teaching mathematics, e s p e c i a l l y as applied to heterogeneous classes i n Senior High Schools, The question seems of considerable Importance yet, although subjective opinions are common, the number of objective studies Is small and the t o t a l of t h e i r findings inconclusive. For an acceptably complete study of such a problem under s t a t i s t i c a l procedure, random sampling of both students and subject matter would be e s s e n t i a l , m the writer's s i t u a t i o n the forraer p a r t i c u l a r l y had to be selected from those r e a d i l y available, hence the p o t e n t i a l accomplishment was a very s l i g h t addition to e x i s t i n g knowledge. As the resources of the average investigator s i m i l a r l y l i m i t the contribution from any single experimental study of t h i s problem, there seems need f o r a considerable number of these to be undertaken. In the s e l e c t i o n of students f o r the sample i n t h i s experiment, the question arose of whether to r e s t r i c t i t to classes taught by the writer or to employ also groups under other teachers i n schools at some distance. P a r t i c i p a t i o n of classes under a number of teachers i s normal to mathematics i n s t r u c t i o n generally and provides a l a r g e r sample, but unless these are accessible f o r close supervision i t i s d i f f i c u l t or even impossible f o r the investigator to observe adequate 53 control of the experimental procedure. It may be that the difference i n c o r r e l a t i o n r e s u l t s between the Kamloops and the other.groups was due to such lack of c o n t r o l . Incomplete measuring of the p r a c t i c a l and the th e o r e t i c a l gains separately must be charged to neglect on the part of the writer, but d i f f i c u l t y of access to the other groups and t h e i r teachers provided the setting f o r that neglect. Inadequacy of measurement generally i s probably the most serious adverse c r i t i c i s m which can be made of thi s experiment. Employment of normally obtainable .standardized tests was not f e a s i b l e as these cover a much broader range of subject matter than was dealt with here. The v a l i d i t y of teacher constructed tests as a measure of achievement i n any si n g l e feature might have been established, but to do t h i s f o r the o r e t i c a l aspects, p r a c t i c a l aspects, and general learning together would have been a tremendous i f not impossible undertaking. An obvious conclusion i s that too many questions were attempted i n one project. The basic question from which th i s experiment was conceived was whether or not use of the inductive approach would be advantageous In heterogeneous classes. It was suggested that a l l pupils i n such groups might s t a r t together with p r a c t i c a l applications and each proceed into theory according to a b i l i t y . The experiment attempted to t e s t only part of the question, i . e . whether learning loss would r e s u l t from the inductive order and s t y l e of presentation. 54 Individual differences i n both rate and extent of progression into theory were avoided. Further study involving this v i t a l feature of the o r i g i n a l l y suggested inductive approach should be worthwhile. BIBLIOGRAPHY A. A r t i c l e s , Books, and Reports to Which Direct Reference  Is Made i n This Thesis; 1. Albers, M. E. and Seagoe, M. V., Enrichment f o r Superior Students i n Algebra Classes, J n l . Ed. Rsch., Mch. 191+7: 1+81-1+95. 2. B i l l e t t , Roy 0 . , Fundamentals of Secondary School Teaching, Cambridge, The Riverside Press, 191+0. 3. B r i t i s h Columbia Department of Education, Divi s i o n of Curriculum, Mathematics 1950. 1+. B r e s l i c h , E. R., How Movements of Improvement Have Affected Present Day Teaching of Mathematics, Sch, S c i . & Math., Feb. 1951: 131-11+1. 5. Brownman, David E., Measurable Outcomes of Two Methods of Teaching Experimental Geometry, J n l . Exp. Ed., Sept. 1938: 31-31U 6. Commission on Post War Plans, National Council of Teachers of Mathematics, Second Report, Math. Teh., May 191+5: 195-221. 7. Dodes, Irving A l l e n , The Science of Teaching Mathematics, Math. Tch., Mch. 1953: 157-166. (A summary of recent developments) • 8. Durell, Fletcher, Mathematical Adventures, Boston, Bruce Humphries Inc., 1938. 9. Fawcett, H. P., The Nature of Proof, Thirteenth Yearbook, - National Council of Teachers of Mathematics. 10. Fehr, Howard F., A Proposal f o r a Modern Program i n Mathematical Instruction i n the Secondary Schools, Sch. S c i . & Math., Dec. 191+9: 723-730. 11. Fowler, Wynette, An Experiment i n the Teaching of Geometry, Math. Tch., Feb. 191+7: 81+-88. 12. Gager, Wm A., Functional Mathematics, Math. Tch., May 1951: 297-301. 56 13• I r v i n , Lee, The organization of Instruction i n Arithmetic and Basic Mathematics i n Selected Secondary Schools, Math. Tch., Apr. 1953: 235-21*0. 11*. Jones, P. S» & others, Report on Progress i n Mathematics Education, Sch. S c i . & Math., June 191*9: lj.65-ll.7il-* 15. Lane, Ruth, The Use of Graded Originals i n Plane Geometry, Math. Tch., Nov. 191*0: 291-300. 16. Lee, Wm, Provision f o r Individual Differences i n High School Mathematics Courses, Math. Tch., Oct. 19il-7: 291*-297. 17. Luchins, A. S. & E. H., A. Structural Approach to the Concept of Areas i n Int u i t i v e Geometry, J n l . Ed. Rsch., Mch. 191*7: 528-533. 18. McCreery, Gene S., Mathematics f o r A l l the Students In High School, Math. Tch., Nov. I9l*8: 302-308. 19. Michael, R. E», The Relative Effectiveness of Two Methods of Teaching Certain Topics i n Ninth Grade Algebra, Math. Tch., Feb. 191*9: 83-87. 20. Reed, Homer B., Psychology and the Teaching of Secondary School Subjects, New York, Prentice H a l l Inc., 1939. 21. Reeve, W. D», S i g n i f i c a n t Trends i n Secondary Mathematics, Sch. S c i , & Math., Mch. 191*9: 229-236. 22. Schorling, R., What's Going On i n Your School? Math. Tch., Apr. 191*8: 11*7-153. 23. University of Chicago (Laboratory Schools), Mathematics Instruction i n the University High School, Publication No. 8, Nov. 191*0. 21*. Wren, F. Lynwood, What About the Structure of the Math-ematics Curriculum? Math. Tch., Mch. 1951: 161-169. 57 B. Additional Works Consulted f o r General Background; 1. Adkins, Dorothy C., Construction and Analysis of Achieve-ment Tests, Washington, U. S. Government Prin t i n g O f f i c e , 19l*.7. . 2. Betz, Wm, Five Decades of Mathematical Reform - Evaluation and Challenge, Math. Tch., Dec. 1950: 377-387. 3. Betz, Wm, Functional Competence i n Mathematics - Its Mean-ing and Its Attainment, Math. Tch., May 191*8: 195-206. I*. B r e s l i c h , E. R., Problems i n Teaching Secondary School „ Mathematics, University of Chicago Press, 191*0. 5. B r e s l i c h , E i R., Curriculum Trends i n High School Mathematics, Math. Tch., Feb. 191*8: 60-69. 6. Brown, K. E., What Is General Mathematics? Math. Tch., Nov. 191*6: 329-331. 7. Brown, K. E., The Content of a Course In General Mathemat-ic s - Teachers' Opinions, Math. Tch., Jan. 1950: 25-30. 8. .Brown, K. E., Why Teach Geometry? Math. Tch., Mch. 1950: 103-106. . 9. Brueckner, L.,J., The Necessity of Considering the S o c i a l . Phase of Instruction i n Mathematics, Math. Tch., Dac. 191*7: 370-371*. 10. Cook, Inez M., Developing Reflective Thinking Through Geometry, Math. Tch., Feb. 19l*3: 79-82. 11. Carpenter, Dale, Planning a Secondary Mathematics Curriculum, to Meet the Needs of A l l Students, Math. Tch., Jan. 191*9: 1*1-1*8. 12. Commission on Secondary School Curriculum of Progressive Education Association, Mathematics i n General Education, New York, D. Apple ton - Century Co. Inc., 191*0. 13. Fawcett, H. P., A U n i f i e d Program i n Mathematics, Sch. S c i . & Math., May 1950: 31*2-31*8. llj.. Gager, Wm A., Concepts f o r Certain Functional Mathematics Courses, Sch. S c i . & Math., Oct. 1950: 533-539. 15. Gager, Wm A., Mathematics f o r the Other Eighty-five Per Cent, Sch. S c i . & Math., Apr. 191*8: 296-301. 58 16. Garrett, Henry E., S t a t i s t i c s i n Psychology and Education, Toronto, Longmans Green & Co., 191+7. 17. Garrison, S. C. & K. C , Fundamentals of Psychology i n Secondary Education (Chapter XIII), New York, Prentice H a l l Inc., 1937. 18. Hassler, J. 0. & Smith, R. R., The Teaching of Secondary Mathematics, New York, The MacMillan Co., 1930. 19. Jones, D. M., An Experiment i n Adaptation to Individual Differences, J n l . Ed. Psy., Vol. 38, 191+9: 257-272. 20. Kinney, L. B., C r i t e r i a f o r Aims i n Mathematics, Math. Tch., Mch. 191+8: 99-103. 21. Laughlin, Butler, Frontiers i n Teaching Mathematics and Science, Sch. S c i . & Math., Mch. 1951: 211-215. 22. National Council of Teachers of Mathematics, The Learning of Mathematics, Twenty-first Yearbook, 1953. 23. National Council of Teachers of Mathematics, The Place of Mathematics i n Secondary Education, F i f t e e n t h Yearbook, 191+0. 2l+. Norberg, Carl G., Mathematics i n the Secondary School Curriculum, Math. Tch., Nov. 191+6: 320-321+. 25. Reeve, W. D„, General Mathematics f o r Grades 9 to 12, Sch. S c i . & Math., Feb. 191+9: 99-110. 26. Schaaf, Wm L,, New Emphases i n Mathematical Education with Reference to Recent L i t e r a t u r e , Sch. S c i . & Math., Nov. 191+9: 639-61+9. 27. Schorling, R., Let's Come to Grips with the Guidance Prob-lem, i n Mathematics, Math. Tch., Jan. 191+9: 25-28. 28. Schmid, John J r . , A Mathematics Course f o r Any Student, Math. Tch., May 191+9: 227-229. 29. Walker, Helen M., Elementary S t a t i s t i c a l Methods, New York, Henry Holt and Company, X91+-6. 30. Wrightstone, J. W., Comparison of Varied Curricular Practices i n Mathematics, Sch. S c i . & Math., Apr. 1935: 377-381, 59 APPENDIX A MIMEOGRAPHED DETAIL OB1 LESSONS Elementary Trigonometry Unit. {Group S£(pU/SA/ceA • i Period 1. Introductions Certain dimensions which are difficult or impossible to measure directly, such as the height of a tree, a building, or a room, can often be calcul-ated i f we can measure one related distance and one related angle. Demonstration Example; (The working of this will be shown by the teacher, one step at a time, with students following and carrying out the operations step by step). Fhat is the height of this classroom? Using a-' sighting protractor and level placed on a desk, sight the intersection of wall and ceiling and read the angle of elevation. Measure the distance along the floor from point under the observer's eye tb the vertical wall. Record these t^o measurements; Angle of elevation j horizontal distance Make a diagram in the space" at the right; mark the angle, base distance, and unknown to be found on i t . In ai right-angled triangle, the ratio of vertical side to base is called the tangent of the lower angle; we can find the value of this from a table on page 512 of the text-book, Writes tangent of is We then write an equation and solve i t Table Practices Find tangent of 7°; 16°; 50°; 53°; 72°; 80°. Practice Exercisess Students work in pairs; sight angle and measure distance together, but each work out calculations and check result with erech other. 1. Find height of a teee immediately outside school. 2. Find height of as pole " » " 3. Find height of school building. 4. Find height of any noint on classroom wall (in case weather does not allow 5. Find height of electric light in classnom. outside work) Elementary Trigonometry Unit. Group£. Period 2. Review Exercise; Find height of a tree, viewed through the classroom window. Three students will measure- outside distance (horizontal) while three- others measure" angle of elevation, ^ o l e class' then works" problem from their dajrep. Demonstration Exercise: "orked by teacher anc1 students together as in that of period 1, (a1) The distance up the slope ofr a h i l l can be measured directly; the angle of e l -evation of its top can be determined by sighting from the foot. Find the vertical height of the h i l l . (A cross-section diagram of the h i l l , drawn on blackboard, will be used) ' Measure and record slope distance Measure and record angle of elevation Make right-angled triangle diagram in speech at right, marking data. In this case we use the ratio of vertical side to hypotenuse; i t is called the sine of the angle. ^rite equation as before (obtaining value of sine from table) Solve equation (b) Calculate the horizontal distance from foot of h i l l to a noint directly under its top. This is worked in a similar manner, but the ratio of the base of the triangle to the hypotenuse is called the cosine of the angle. Practice Exercises: (forking in pairs as in period 1). Measure the angle of ascent of a flight of steps; measure the sloping distance along the steps from bottom to top. Calculate the vertical rise. Measure thelength and angle of elevation of a sloning board. Calculate the height of its upper end and also the horizontal distance i t covers. Review of differences between tangent, sine", and cosine. Elementary Trigonometry Unit. Group A. Periods 3*& 4. Brief review of sine, cosine, andtangent from blackboard diagram. Brief review of system of writing equation from diagram with data, and solution. .Practice Exercises; Each student is to work at his or her own rate. Individual hel| will be given by teacher as;requested. Papers will be collected at end of period 3 ,and reissued for period 4. The last half of period 4 will be devoted to class *checking of answers?and corrections^ Work on foolscap. ' m a a u » and BC 2, In the above diagram, i f angle A is exactly 27 degrees and AB is 200 yds, find the length of AC using trigonometric function value from table. H is of angle A; that i s , ±3 27° = . AB 200 Then AC = . x 200 = Practice Exercises^; Each student is to work at' his or her own rate. Individual help will be given by teacher as requested. Papers 5will be collected at end of * period 4 and reissued at beginning of period 5. Answers to the- first five exercises will be given at the beginning of period 5. All work is to be handed in again at the end of period 5. Work on foolscap. 1. Find "h» l0* jh 2. Find "w" 3. Find "1" 4. Find "a* 5. Find "1" 6. From a point on level ground 250 feet from the foot of a tree, the angle of elevation of its top is 12 degrees. How t a l l is the tree? 7. A highway slope's upward on a steady climb at an angle of 7 degrees for a distance of one-half mile. How many feet is the top higher than the foot of the hill? 8. A fire-truck ladder is raised until i t is at an angle of 52 degrees from hori-zontal, and is extended until its length is*85 feet. How high is the upper end of the ladder above its base? How far out horizontally does i t extend? 9. If the fire>-truck ladder is extended to a length of 100 feet' and raised until its 1 upper end is 75 feet above- the base-, what1 is the angle- of elevation? 10. An observer on a-bridge;160 feet above the water sees a boat downstream at an angle of depression of 15 degrees. How far is the boat downstream from the bridge? 11. An ordinary ladder is considered safest when i t is placed at an angle of 75 de-grees from horizontal." How far from the foot of a vertical wall should a 60 foot ladder be placed i f this ruleis followed? 12. Two towns A and B are 350 miles apart in a straight line. Town B is 37 degrees west of due north from town A (a) By how many miles is B further North than A? (b) By how many miles is B further West than |A? 13. Problem 1, page 319 of text-book 14. Problem 3, « » » 15. Problem 4, " " « Elementary Trigonometry Unit. Group £. Periods. •> what are--these ratios: Sine, Cosine, and Tangent? A standard method of naming the sides of right angled triangles has been adopted. One of the acute angles is taken as a reference point and the sides are called: the hypotenuse the side opposite to the angle the side adjacent to the angle 5 The SINE (Sin) of the angle is alrays. s i d e opposite to angle hypotenuse The COSINE (Cosin, Cos7) of the angle is always g l d g gjl^ggg j° ^ The TANGENT (Tan) of the angle iff always: side opposite to angle Side adjacent to angle What happens to these ratios when triangles differ in length of sides but angles remain constant? In the figures immediately below, BAC and EAD are equiangular right-angled t r i -angles? side BC'is 5 cm., side ACT is 4' cm., side ED i s 4§ cm., side AD is 6 cm. t s A C A (In the exercises below, the length of the hypotenuse may be found by calculation of measurement 1. Write: tangent of angle A is s ^ e ~ s=ide -For triangle BAC, tangent A = F o r triangle EAD, tangent A = 2. Write: sine of angle A is 8 i d e  For triangle BAC, sine A . . F o r triangle EAD, sine A *= 5. Write: cosine of angle A is s i d e " '. • For triangle BAC, cosin A = For triangle EAD, cos A = 4. Reduce each of the above-ratios to itis lowest terms and complete this statement: If an angle remains: constant then the sine-, cosihGP, and tangent each  _ no matter how large the triangle. 5. Reduce^  each of the above* ratios tb a decimal: Sin A" Cbs A Tan A 6. Measure angle A with protractor, find its sin, cos, and tan from tables and check your values of No. 5. 7. Measure angle B (note that A + B must total 90°) and find from table the values of sin B , cos B ' • and tan B 8. From the triangle BAC above write the values of sin P, cos' B, and tan B from the lengths of the sides7. Reduce each to decimal and compare with No. 7. Elementary Trigonometry Unit. Gram)A. Period^ . » * Review; Study from previous page followed by oral d r i l l on; (1) Definitions of Sine, Cbsine, anri Tangent. (2) If angle & remains constant, what happens" to these ratios for differ-ent sized right-angled triangles? Class Exercises; The following are to be worked by each student with explanations and checking at frequent intervals as* for those of period 1: A. In each of the three right-angled triangles below, the hypotenuse AP is 5 cm. Measure the other two sides of each triangle and write, first as common fractions, then as decimals, the values of Sin Aj Cos A; Tan A. Sin A Cos A Tan PI Complete the statement; As angle A increases, Sin A becomes , Cosin A becomes , Tangent £ becomes . Check your statement from the values* given of 0 these functions for various sized angles in the tables at the back of the text-book. From these same tables and the ratios worked out above-, find, to the nearest degree the size of each angle A in the above figures. B. 1, Construct an angle whose tangent is 5/8; that is, draw a right-angled triangle which has a base of 8 units and an altitude of 5 units, Mark the angle. 2. Reduce 5/8 to a decimal and find from table what size the angle should be. Check your construction by measuring the angle with protractor. 3. Calculates (Pythagoras) the length of the hypotenuse of this triangle to the nearest tenth. 4. Write the value of the sine of the angle", using hypotenuse just calculated, reduce i t to a decimal and compare with the value given in table. 5. Write the value of the cosine of the angle, using hypotenuse calculated, reduce i t to a? decimal and corn-Dare with table. C. Write from memory the definitions of sine, cosine, and tangent. ,.. Element aery Trigonometry Unit. Group /[. Period 7. Practice Exercises: Work on this sheet or use additional paper as necessary. Each student i s to proceed at his or her own rate. Help may be gained by restudy of pre-vious page; individual assistance"will be given also by teacher as' requested. A l l work i s to be handed in a-t the close of the period. 1. Construct an angle whose sine i s 3/7. Measure with protractor and check with table 2. Construct an angle whose cosine i s 4/9. Measure and check. 3. Construct an angle whose tangent i s 2/3. Measure and check. 4. If the tangent of an angle i s 5/12, calculate 1: (a) i t s sine (b) i t s cosine 5. If the cosine'of am angle is? 4/9, cra.lcru.late": (a) i t s 1 sine (b) its--tangent. 6. Construct an angle whose sine" is- .5 7. Construct an angle- whose- tangent" i s 2§. 8. Exerciser 5, 6, and 12 on page 316 61F ttext-book. Elementary Trigonometry Unit. (GROUP bJ j^poe/i^ces Period 1. Introduction; Recently we proved the theorem: "If two triangles are equiangular their corresponding sides are proportional." The ratios of sides of equiangular right-angled triangles are of great importance in mathematics and are widely used. Exercises; The following are to be read and worked or completed by each student. As" these are demonstration and study examples, explanations will be given and re-sults checked as the work proceeds'. 1. BAC and EDF, shown immediately below, are equiangular right-angled triangles 2. Construct a right-angled triangle lettered like the sample BAC above but having sides: a» » 3 cm; b => 4 cm. (Use the left side space below) With protractor, measure angle A and write its 1 sixer here degrees. Calculate the length of side~"c" (Pythagoras theorem) ; check by measuring. Write in figures, first as common fractions, then as decimals, the ratios: (i) a- _ m . (ii) b = s. ( i i i ) a = = . c c b 3. In the right hand snace-abovej construct another right-angled triangle, lettered the same, but having side" "bJ' 6 cm; make- angle A" the same size- as in No. 2 by using your protractor. Measurer the other two sides after the triangle is drawn and write the ratios-, f i r s t as common fractions, then as decimals: (1) a _ _ i (ii) b _ . ( i i i ) a _ . c ~ c ~ ~ b Since angle A remained constant, would you expect these ratios to be the same for both triangles? 4. If side b is 10 f t . and angle A the same, calculate side a 5. If side c is thirty miles and angle A the same, calculate- sides a and b Definitions? Because triangles can be lettered in many ways, a standard means of naming sides has been adopted to avoid confusion. One of the acute angles is taken as a reference point and the sides are spoken of as: the hypotenuse the side opposite to the angle the side adjacent to the angle The ratios have been given the following names: side °PP^lte^to angle l g c a U e d ^ ( g S a ) o f ^ a n g l e # side adjacent to angle i g ; COSINE (Cosin; Cos) of the angle, hypotenuse side, opposite- to angle ± T A N G H N T ( T a n) o f t h e side adjacent to angle Exercise: Identify the ratios Sin A, Cos A1, and Tan A' of No. 2 above-. 1 Check their values with those given for angle A in tables at back of text Elementary Trigonometry Unit. Ground. Period £ Review; Study from previous page followed by oral d r i l l on: (1) Definitions of Sine, Cosine, and Tangent. (2) If angle i? remains constant, what happens7 to thesre ratios for differ-ent sized right-angled triangles? Class Exercises; The - following are to be worked by each student with explanations and checking at frequent intervals as7, for those of period 1: A . In each of the three right-angled triangles below, the hypotenuse AP is 5 cm. Measure the other two sides of each triangle and write, first as common fractions, then as decimals, the values of Sin Aj Cos A; Tan £. P Sin A Cos A Tan A: Complete the statement: As angle A' increases, Sin A becomes , Cosin A becomes , Tangent A becomes . . Check your statement from the values' given o f these functions for various sized angles in the tabbies at the back of the text-book. Prom these same tables and the ratios worked out above, find, to the nearest degree the size of each angle A in the above figures. B. 1, Construct an angle whose tangent is 5/8; that is, draw a right-angled triangle which has a base of 8 units and an altitude of 5 units* Mark the angle. 2. Reduce 5/8 to a' decimal and find from table what size the angle should be. Check your construction by measuring the angle with protractor. 3. Calculate* (Pythagoras) the length of the hypotenuse of this triangle to the nearest tenth. 4. Write the value of the sine of the angle-, using hypotenuse just calculated, reduce i t to a decimal and compare with the value given in table. 5. Write the value of the cosine of the angle, using hypotenuse calculated, reduce i t to as decimal and compare with table. C. Write from memory the definitions of sine, cosine, and tangent. Elementary Trigonometry Unit. Group3_. Period3t. Practice Exercises; Work on this sheet or use additional paper as necessary. Each student is to proceed at his or her own rate. Help may be gained by restudy of pre-vious page; individual assistance will be given also by teacher a3S requested. All work is to be handed in at the close of the period. 1. Construct an angle whose sine is 3/7. Measure with protractor and check with tffble 2. Construct an angle whose cosine is 4/9. Measure and check. 3. Construct an angle whose tangent is 2/3. Measure and check. 4. If the tangent of an angle is 5/12, calculate* (a) its sine (b) its cosine 5. If the cosine of an angle is? 4/9, calculate: (a?) its' siner (b) its'tangent. 6. Construct an angle whose sine is .3 7. Construct an angler whose- tangent*" is 2§. 8. Exercises'5, 6, and 12 on page 316 6fF text1-book. Elementary Trigonometry Unit. Group B. Periods 4 & 5 Demonstration Exercises: These are to be worked by each student with teacher showing steps and method on blackboard as necessary. 1. In the accompanying right-angled triangle BPC, or " of angle A 3 — = .45 If AB actually is 100 yds, then: BC 9 or, using decimal, BC' 100 " 20 100 " ' ° and BC » and BC 2. In the above diagram, i f angle A! is exactly 27 degrees and AB is 200 yds, find the length of AC using trigonometric function value from table. H is of angle A; that i s , is 27° = . AB 200 Then ACT = . x 200 = Practice Exercise?* Each student is to work at his or her o^ m rate. Individual help will be given by teacher as requested. Papers will be c ollected at end of neriod 4 and reissued at beginning of period 5. Answers to thff firs t five exercises will be given at the beginning of period 5. All work is to be handed in again at the end of period 5. Work on foolscap. 1. Find »h" 2. Find "w" S. Find "1" 4. Find "ar» 5. Find "1" 6. From a point on level ground 250 feet from the foot of a tree, the angle of elevation of its top is 12 degrees. How t a l l is the tree? 7. A highway slopes upward on a steady climb at an angle of 7 degrees for a distance of one-half mile. How many feet is the top higher than the foot of the hill? 8. A fire-truck ladder is raised until i t is at an angle of 52 degrees from hori-zontal, and is extended until its length is 585 feet. How high is the upper end of the ladder above its base? How far out horizontally does i t extend? 9. If the fire>-truck ladder is extended to a length of 100 ffeet' and raised until i t s upper end is 75 feet abover the baser, what-is the angle of elevation? 10. An observer on a'bridge:160 feet above the water sees a boat downstream at an angle of depression of 15 degrees. How far is the boat downstream from the bridge? 11. An ordinary ladder is considered safest when i t is placed, at an angle of 75 de-grees from horizontal. How far from the foot of a vertical wall should a 60 foot ladder be placed i f this ruleis followed? 12. Two towns A and B are 350 miles apart in a straight line. Town B is 37 degrees west of due north from town A (a-) By how many miles is B further North than A? (b) By how many miles is B further West than 'A? 13. Problem 1, page 319 of text-book 14. Problem 3, " " » 15. Problem 4, " » " Elementary Trigonometry Unit. Grous _ ,° Period 6. Check answers and make corrections to exercises of last two neriods (15 minutes) Demonstration Example; (This will be shown by the teacher with students using his observed data to comnlete the solution). "tiat is the height of this classroom? Using a sighting protractor and level placed on a desk, sight the intersection of wall and ceiling and read the angle of elevation. Measure the distance along the floor from point under the observer's eye to the vertical wall. Record these two measurements; Angle of elevation ; horizontal distance ^orking on this -oaper, make a diagram, mark dita, and work out the height. Practice Exercises: Students work in pairs; sight angle and measure distance together, but each work out calculations and check result with each other. 1. Find height of a tree immediately outside school 2. Find height of a pole " " » 5. Find height of school building. 4. Find height of any ooint on classroom wall (in case of unsuitable weather for 5. Find height of electric light in classroom. outside rork) Period 7; Completion of unfinished work of period 6 (5 to 10 minutes) Demonstration Exercise; Teacher demonstrate? and students work from his data as before. In this case one or two students may make the actual measurements for the class. , The distance up the slope of a h i l l cnn be measured directly; the angle of elev-ation of its top can be determined by sighting from the foot. ImmmmibmBrTgifflBitomramm (A cross-section of the h i l l , drawn on the blackboard, will be used) (a) Find the vertical height of the h i l l . (b) Find the horizontal distance from foot of h i l l to a "-joint directly unr'er its to Ti. Practice Exercises; parking in nairs as- in period 6). Measure the angle of ascent of a. flight of stairs; measure the sloping distance along the steps from bottom to top. Calculate the vertical ripe. Measure length and angle of elevation of a sloping board. Calculate the height of its upper end and also the horizontal distance i t covers. 60 Chords in a Circle Unit. (Group As.) 5^M^-B-Period 1^ Introduction; Any straight line joining two points on the circumference of a circle is called a- chord. In studying these, the line joining the mid-point of any chord to the centre of the circle i s a key line, ^e can prove certain features important enough to be classed as theorems. Theorem: Ther straight line joining the centre of a circle to the mid-r>oint of a chord is at right angles to the chord. Data; Let ""B be~ any chord with C as its nid-point, and 0 be the centre^ of the circles Aim: To prove that OCT is perpendicular to .'J?. Construction: Join OA and Proof: In the triangles OCT and (to be completed with help) Brief review questioning on main features of theorem and proof: What two things are given about the line OCT? What third feature i s to be Droved? "faat i s the general method of oroof? What f i n a l sten i s necessary 'after proving triangles congruent? Write again on foolscap the comlete"'oroof of this theorem. Theorem: The~line drawn from the centre of a circle perpendicular to a chord bisects the chord. What two things are given in this theorem? What is to be proved? On foolscap, write the general enunciation, draw the figure, write down in proper form the data and aim. (Upon completion these will be checked with blackboard sample) Can this theorem probably be proved by congruent triangles? What construction is necessary? Students will attempt to coanlete this proof, fflta Sanrole for checking will then be provided on blackboard. , Chords in a Girale Unit. Perioda*?^ 3 Group As Theorem; The perpendicular bisector of a chord passes through the centre of the circle. On foolscap, draw a suitable figure, and write down in good form the data and sim. (To be checked with sample on blackboard before proceeding further. Demonstration of proof will be given. Students then write out proof for themselves. Exercises; 1. Prove that the .distance- of any chord from the centre of BJ circle i a equal to the square root of (the square of the radius minus the square of half the chord). 2. If two equal chords are drawn in a circle proven that they are equidistant from the centre. 3. State and prove?the converse of exercise 2. 4. AB and CD are two chords•> of ee circle. AB is-longer than CD. Prove-that AB is closer to the centre? than CD. 5. Two circles whose centres are 0 and Q respectively intersect at two points, A and B. The straight line AB is called the common chord of the two circles. Draw two such circles with their common chord and mark its mid-point C. Join OC and QC, and prove that OGQ forms one atraight line. (TMs line is called the line of centres. 6. In the accompanying diagram, 0 and Q1 are centres of the two^cixfiles" and OQ the line of centres. AB is the common chord. . XBY is a straight line perpendicular to AB. Prove that XY equals twice the line of centres. 7. D s In the diagram at the right, AB is any straight line and CD is the perpendicular bisector of AB. Quote a proven reference to show that Mm i f the circumference of any circle' passes through points A and B, its centre must lie on the line - CD. 8. In the diagram a^Uifec-jssgfat, 0 is? the centre of the circle of which only is shown. AB i a a chord r„nd OCD the perpendicular bisector. Using Pythagoras1 rule, work out a formula for the length of CD in terms of radius and chord. an arc o Chords in a Circle Unit. Group / \ Period ^ / Construction Exercises: (Geometrical construction using ruler and comoasses only) 1. A circle is to be drawn through two given points, A, and B. (1) Join AB (ii) Construct the perpendicular bisector of AB ( i i i ) Taking any ooint, 0, on this perpendicular bisector SES- centre, with radius OA, draw the circle. /\ • ' £• How many such circles aan be drawn? 2. A circle is to be drawn through three" given points, A, B, and C, which are not in one straight line. / ^ (i) Join AB and construct the perpendic-ular bisector, (ii) Join BC and construct the perpendicr- /\ • ular bisector. ( i i i ) With 0, the point where these lines fi> intersect, as centre and radius OA, draw the circle. - V 3. Given an arc of a circle, locate the centre and complete the circle. 4. A circle is to be drawn through the three vertices of a given triangle: (a) Acute angled triangle. (b) light angled triangle. (c) Obtuse angled triangle. Chords in a Circle Unit. Group _/\ Periods ' b Review Exercise of Right-angled Triangle Calculations; This is to be worked by a l l students immediately. Fork will be checked and explanations given before next sec-tion is begun. _ OCB is a right-angled triangle having the right angle at C. (a) If OC is 4 cm and CB is 7 cm, calculate the length of OB. (b) If OCT is 5 cm and OB is 8 cm, calculate the-length of CB. Calculation Exercises Involving Chords: (work on foolscap) 1. In the figure below, 0 is the centre of the circle and OC the peroendicular bisector of the chord AB. Join OB and name the right-angled triangle. 0 ! If OCT is 4 cm and chord A'B is 14 cm: (a.) How long is CB? A\ 7* 7*B (b) Calculate the length of the radius OB. 2. In the figure below, 0 is the centre of the circle and OC is the perpendicular bisector of the chord AB. Complete a right-angled triangle and name i t . 0 ^ If OC is 5 cm and the radius is 8 cm: (a) Calculate the length of CB. C / y (b) How long is the chord AB? 3. In the figure_below, 0 is the centre of the circle and OCT) the perpendicular bisector. If' CD is 5 inches and the radius 9 inches: (a) Calculate the length of OC. ^ j (b) Calculate the length of CB and then of AB. 4. A certain circle has a 16 foot chord placed so that its-greatest distance from the circumference is 3 feet. Calculates the'radius of the circle. 5. An arch type' bridge i s to be built over a canyon. The diagram shows AB, the span C*""" of the bridge which is 240 feet, and the arch ACB, an arc of a circle whose radius is 135 feet. Calculate the height of the middle point of the arch above AB. 6. The cross-section of a tunnel, circular except for a flat bottom, is shown in the * ^ accompanying diagram. If the chord AB is 10 feet, and the diametor of the circle is 20 feet, calculate the height CD. 7. A chord of a circle is 24 inches long. The radius of the circle is 15 inches. How far is the chord from the centre of the circle? 8. Two chords of a circle, AB and CD ers shown in the diagram, are 4 inches apart. Q Chord AB is 24 inches and CD is 16 inches long. Cal-13 culate the-radius of the circle. 0 Additional problems will be found on pages 456-7 of text-book: Education  Through Mathematics. Chords in a Circle Unit. f^ Group Periods / v l Review Exercise of Right-angled Triangle Calculations: This is to be worked by a l l students immediately. Fork will be checked and explanations given before next sec-tion is begun. OCB is a right-angled triangle having the right angle at C. (a) If OC is 4 cm and CB is 7 cm, calculate the length of OB. (b) If OCT is 5 cm and OB is 8 cm, calculate the-length of CB. Calculation Exercises Involving Chords: (Work on foolscap) 1. In the figure below, 0 is the centre of the circle and OC the perpendicular bisector of the chord AB. Join OB and name the right-angled triangle. 0 1 If OCT is 4 cm and chord AB is 14 cm: (a) How long is CB? A\—7*. ~f& (b) Calculate the length of the radius OB. 2. 3i In the figure below, 0 is the centre of the circle and OC is the perpendicular bisector of the chord AB. Complete a right-angled triangle and name i t . 0 \ If OC is 5 cm and the radius is 8 cm: (a) Calculate the length of CB. C / ^  (b) How long is the chord AB? In the figure_below, 0 is the centre of the circle and OCD the perpendicular bisector. If" CD is 5 inches and the radius 9 inches: (a) Calculate the length of OCT. (b) Calculate the length of CB and then of AB. 4. A certain circle has a 16 foot chord placed so that its-greatest distance from the circumference is 3 feet. Calculates thar radius of the circle. 5. An arch type bridge is' to be built over a canyon. The diagram shows AB, the span C~"~---\ of the bridge which is 240 feet, and the arch ACB, an arc of a circle whose radius is 135 feet. Calculate the height of the middle point of the arch above AB. Ac  6. The cross-section of a tunnel, circular except for a flat bottom, is shown in the f^-^ accompanying diagram. If the chord AB is 10 feet, and the diametor of the circle is 20 feet, calculate the height CD. 7. A chord of a circle is 24 inches long. The radius of the circle is 15 inches. How far is the chord from the centre of the circle? 8. Two chords of a circle, AB and CD as shown in the diagram, are 4 inches apart.-Q Chord AB is 24 inches and CD is 16 inches long. Cal-3 culate the-radius of the circle. 0 Additional problems will be found on pages 456-7 of text-book: Education  Through Mathematics. Chords in a Circle Unit. Group & Period 3 Construction Exercises: (Geometrical construction using ruler and comoasses only) 1. A circle is to be drawn through two given points, A, and B. (1) Join AB (ii) Construct the perpendicular bisector of AB ( i i i ) Taking any Doint, 0, on this perpendicular bisector as1 centre, with radius OA, draw the circle. A ' ' & How many such circles aan be drawn? 2. A circle is to be drawn through three-given points, A, B, and CT, which are not in one straight line. (i) Join AB and construct the perpendic-ular bisector, (ii) Join BC and construct the perpendio-ular bisector, ( i i i ) With 0, the point where these lines intersect, as centre and radius OA, draw the circle. 3. Given an arc of a circle, locate the centre and complete the circle. A 6 • c 4, A circle is to be drawn through the three vertices of a given triangle: (a) Acute angled triangle. (b) Eight angled triangle. (c) Obtuse angled triangle Chords in a Circle Unit. Group B. Period 4. Introductions In the calculation and. construction exercises we have just completed, a line similar to OC in the accompanying figure appar-ently! (i) passes through the centre- of the circle, (ii) passes through the mid-point of the chord, ( i i i ) is" perpendicular to the chord. have assumed that i t does a l l these three at once, and while high probability assumptions have to be used as the basis of action in many features of l i f e , yet i f proof is possible then we have a mmga stronger basis. For example, a construction comnany spending many thousands of dollars' on an arch type bridge such as in exercise 5 of page 1 would appreciate such a proof before investing their money. Theorem; The1 straight line joining the centre of a c i r d e to the raid-point of a chord is at right angles to the chord. Data; Let ^13 be- any chord with C as its mid-point, and 0 be the centre^ of the circle". Aim; To prove-that OC is perpendicular to AB. Construction: Join OA and Proof: In the triangles OCA and (to be completed with help) Brief review questioning on main features of theorem and proof: What two things are given about the line OC? What third feature is to be proved? What is the general method of oroof? What final step is necessary after proving triangles congruent? Write again on foolscap the completer proof of this theorem. Theorem: The line drawn from the centre of a circle perpendicular to a chord bisects the chord. What two things are given in this theorem? What is to be proved? On foolscap, write the general enunciation, draw the figure, write down in proper form the data and aim. (Upon completion these will be checked with blackboard sample) Can this theorem probably be proved by congruent triangles? What construction is necessary? Students will attempt to complete this proof, fflh Sample for checking will then be provided on blackboard. Chords in a Girde Unit. Group 3 PeriodsJf v L , Theorem; The perpendicular bisector of a chord passes through the centre of the circle. On foolscap, draw a suitable figure, and write down in good form the data and sim. (To be checked with sample on blackboard before proceeding further. Demonstration of proof will be given. Students then write out proof for themselves. Exercises: 1. Prove that the distance of any chord from the centre of a circle- i a equal to the square- root of (the square of the radius minus the square of half the chord). 2. If two equal chords are drawn in a circle prover that they are equidistant from the centre. 3. State and proves the converse- of exercise 2. 4. AB and CD are two chords-of & circle. .'B is longer than CD. Prove that AB is closer to the centre? than CD. 5. Two circles whose centres are 0 and Q respectively intersect at two points, A and B. The straight line AB is called the common chord of the two circles. Draw two such circles with their common chord and mark its mid-point C. Join OC and QC, and prove that OCQ forms one straight line. (His line is called the line of centres. 6. In the accompanying diagram, 0 and (J are centres of the two^^cirfiles and OQ the line of centres. AB is the common chord. _ , XBY is a straight line perpendicular to AB. ^ Prove that XY equals twice the line of centres. O 7. D s In the diagram at the right, AB is any straight line and CD is the perpendicular bisector of AB. Quote a proven reference to show that Mm i f the circumference of any circle passea through points A and B, its centre must l i e on the line CD. 8. In the diagram a.£uthoTasagnt, 0 is* the centre of the circle of which only an arc is shown. AB i a a chord and OCD the perpendicular bisector. Using Pythagoras' rule, work out a formula for the length of CD in terms of radius and chord. O 61 APPENDIX B TESTS Elementary Trigonometry Unit. TEST. Student's name X Part A. (Values, l_each) The accompanying triangle BAC is right-angled at C. XB and ACT are parallel horizontal lines. Underline the correct answer to each of the f o l -lowing: c 1. The angle of elevation of point B is: ABX; ABC: BAC; XBA. 4. The tangent of angle A i s : i s : AC; BC; AB; i i s : AC; BC; AB; BC BC AC AC AC AB AB BC BC AB AC AC AB AC AE BC AB FB AC AC AC BC BC AF AF AB AC AC PC BC EC AF i AC is : 4; 40; , then AC is-. 10; 6. The jjpsine of angle B i s : 7. The^s-ine of angle A i s : 8. If AB is 7 and BC is 3, then  «V40~j V5B. 9. If | | = | and FA is'IS units  then AC is-. 12|; 14; 18. 10. If H - .3652 and AF is 200 units, then BC i s : 18.26; 182.6; 70; 73.04 Part B. Work ae directed in spaces provided. (Value of each is given in margin at right). Values 1. Using the given framework of straight lines in which the angle C is a right angle, con-£. struct accurately an angle Tfhose sine is 3/5. -c 2. Wishing to determine the height of a t a l l building, an observer, from a position 500 feet away on level ground, sights the angle of elevation of its top as 16 degrees. On the diagram given immediately below: A (a) Which is the angle of elevation? / I if (b) T%ich side represents the building? (<r) What function of the angle would ~& C you use to solve' the problem?....... (Do not work any further on this question) 3. If sine A is 2/7, cnlculate cosine A (leaving answer in surd form) 2 4. Using the given framework of straight lines which has angle C a1 right angle, construct ac*-curately an angle whose tangent is .4 Elementary Trigonometry Unit TEST Page 2. Student's name. 5. An observer in an aeroplane, known to be 5000 feet above level ground, sights a town ahead at an angle of depression of 4*0 degrees. Complete the given diageam and: (®) Mark the angle of depression. o (b) To solve this problem you should i use the (tell which function) j °Z degrees. ; (No other work is required on this problem) 6. If tangent A is* 5/6, cffllculst.-, sin A (Lsr.ving answer in surd form) z 7. Sighted from the bottom of a h i l l , tho an^le off' .Vlevfticv. of its top is 24 degrees. The measured distance up the- ever* slope la-1800 tZ*t. Wh'.t is the-vortical height of the hill? (Work thia problem usin^ on-3 of tw <*ivon function value::;: Sin 24 ia. .4067; aos- 24 ie t-r. ;»4. is .4452) 8. Complete* the following: and i t s z #a an angler bscomeRr larger, its- tangent deoreaistras. Exp. Unit II - Chords in a Circle-. PRETEST. Namer (Items 1 to 6 are valued at 1 mark each; items' 7 to 10 at 6 marks? each). 1. Complete this statement: The straight line drawn from the centre? of a circle* to bisect at chord is^ also * 2. Complete the statement: Of two unequal chords in a* aircler, the one farther from the centre is • 3. Complete the statement: If two chords of a circle are? the same distance from the centre, they . 4. In the accompanying figure, the line AB is called the . 5. The figure at the right shows an arc of » circle and a chord. If the chord i s 9 inches from the centre of the circle, and the radius is 15 inches, what i s the great-est height of the arc at CD? 6. In the accompanying right-angled triangle, AB is? 9 units and AC is 5 units. Calculate BC, leaving answer in surd form. BC = 7. Construct a circle (geometrical construction) to pass through the-vertices of the given triangle ABC. B 8. On the reverse side of this page, prove: that: The-perpendicular drawn to a chord from the centre of a circle bisects the chord. In the accompanying diagram, 0 i s centre of the circle whose- radius is 12 feet. If chord AB is 9 feet from 0, calculate* the length of AB. 10. The tunnel ACB is - 1 m. circle"! whose? lower part has been cut off by the-chord AB. If CD, the-greatest'-height of the tunnel, is 20 f t . , and AS i'ss 16 f t . , osilculateF ther radius of the circle* Exp. Unit II.- Chords in a Circle. Final TEST. Name (Items 1 to 6 are valued at 1 mark each; items 7 to 10 at 6 markd each). 1. Complete the statement; The straight line drawn from the' centre of a. circle perpen-dicular to ai chord also 2. Complete the statements Of two unequal chords of a circle, the one nearer the centre is • 3. Complete the statement: If two chords of a circle are equal, they are the centre. 4. In the accompanying figure, the line CD is called the . 5. The figure at the right shows an arc of a- circle and a chord. If the greatest height of the arc at CD is 5 inches, and the radius is 13 inches, how far is the chord from the centre of the circle? 6. In the accompanying right-angled triangle, AB is 7 units and BC is 4 units-. Calculate ACT, leaving answer in surd form. AC = a 7. Using ruler and compasses only, construct a circle that will pass through the three given points A, B, and C. • 0 8 • 8. On the reverse side of this page, prove that: The straight line joining the centre of a circle to the mid-point of a chord is perpendicular to the chord. 9. In the accompanying diagram, 0 is centre of the circle A whose radius is 12 feet. If chord AB is 16 feet long, calculate the distance from 0 to AB. 8 10. ACB represents a curved mirror whose chord AB is 20 inches long, while CD, the per-pendicular bisector, i s 3 inches. Calculate the-radius of the arc. D s^Zv-d a-J-^-^-i -A * e^^>4 ^*>^i-t & 62 APPENDIX C SAMPLE OF CALCULATIONS Equating of Kamloops Groups - I.Q. P u p i l No. Group A Group B X 2 X X' 1 125 /16 256 125 " 2 122 /13 169 122 A 3 3 121 /12 11+1+ 118 A I 1+ 119 /10 100 117 A 8 5 116 / 7 1+9 116 t 7 6 116 / 7 1+9 115 A 6 7 115 t 6 36 112 / 3 8 110 1 111 / 2 9 108 - 1 1 109 0 10 108 - 1 1 108 - 1 11 101+ - 5 25 106 - 3 12 103 -6 36 106 - 3 13 103 - 6 36 105 - k 11+ 102 - 7 1+9 101+ - 5 15 101 - 8 61+ 101+ - 5 16 99 -10 100 102 - 7 17 98 -11 121 93 -16 18 97 -12 92 -17 1967 7 3 1965 J"? (*>) X a 109.3 Assumed X\ a 109 • 109.2 109 256 169 81 61+ k? 36 9 h 0 1 9 9 16 25 25 1+9 256 289 T3H7 S /3ZI N J / 3 V 7 _ /JL S.7 63 Equating o£ Kamloops Groups - 1s t Term Marks Pupil No. Group A Group B X x' (x») 2 X x« ( x ' ) 2 1 81 2 61+ 3 81 k 77 5 82 6 75 7 63 8 78 9 80 10 k2 11 87 12 56 13 51 tk 68 15 86 16 kk 17 60 18 ?8 1*93 /12 93 frk 576 - 5 25 ?k A 5 225 A 2 68 - 1 1 < 8 6ff 79 /10 100 A 3 169 82 A 3 169 36 72 / 3 9 - 6 36 56 -13 169 ^ 9 81 62 - 7 It? 16 A i 121 73 -27 729 76 k-9 /18 324 72 / 3 9 -13 169 66 - 3 9 -18 32if 71 / 2 - 1 1 58 -11 121 A 7 289 53 -16 256 -25 625 51 -1.8 32% - 9 81 70 t 1 1 -11 121 -11 121 m 3m __15 X z 6 8 . 5 69.1 Assumed X s 69 - - - 69 /3.? = //•/ 6k Equating of Kamloops Groups - 1st Term Marks (continued) Estimated Standard Deviation of a population from the combined Information of two samples: (N.B» Since the difference between the assumed mean and the actual mean^Is very s l i g h t i n each case, the ^ x ' and the ^(x>) , immediately avai l a b l e from the previous page, have been used f o r ^ x and ^ j t i n the formula below). Standard Error of the Difference between the two samples when assumed to be drawn from the same population: C r i t i c a l Ratio: t = A / 1 , - Niz 4.3 = 0.\H 65 General Achievement of Kamloops Groups i n Unit I Pupil No, Group A Gi*oup B 1 2 3 \ 6 7 8 9 10 11 12 13 15 16 17 18 27 21 28 29 29 25 27 21+ 23 16 25 17 19 23 24 15 23 11 4 2 5 6 6 2 1 0 7 2 6 4 0 1 8 0 6 16 k 25 36 36 Jt 1 0 k9 3^ 16 0 1 64 0 16 25 27 24 29 26 22 12 28 25 21 2k 21 20 2^ 15 17 18 m 2 3 5 2 7 ll-0 -10 A 6 7 3 1 2 1 2 2 7 5 4 9 25 4 49 16 0 100 36 9 1 4 l X % 16 X s 22.9 Assumed X g 23 -22.3 22 5 = 5 = St. 3 yy + 35L_ 66 C o r r e l a t i o n Between I.Q. and Un i t I Test Scores (Kamloops Group A) (I.Q. dev. (Test Score dev. from page 62) from page 6£) P u p i l No* x y xy 1 A 6 / k 2 A 3 - 2 3 A 2 A * k /10 A 6 5 A 7 ^ 6 6 ^ 7 A 2 7 , A 6 ^ k 8 / 1 / 1 9 - 1 0 10) -1 - 7 11 - 5 12 - 6 - 6 13 - 6 - k 1* - 7 0 1$ - 8 16 -mo> - 8 17 - i i 0 18 -12 - 6 M -26 /60 /60 / 1 0 / 7 -10 /2k 0 - 8 /80 0 Prom page 62, x 2 = 1381 Prom page 65, ^ _ x 2 s 3kk (N.B. As noted on page 6k, here again the d i f f e r e n c e between assumed mean and a c t u a l mean i s so s l i g h t i n each case t h a t x 1 has been used f o r x ) . r =-. 2* + 

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