Springer Texts in Statistics Advisors: Stephen Fienberg Ingram Olkin Springer Texts in Statistics Alfred Elements of Statistics for the Life and Social Sciences Blom Probability and Statistics: Theory and Applications Chow and Teicher Probability Theory: Independence, Interchangeability, Martingales. Second Edition Christensen Plane Answers to Complex Questions: The Theory of Linear Models du Toit, Steyn and Graphical Exploratory Data Analysis Strumpf Kalbfleisch Probability and Statistical Inference: Volume 1: Probability. Second Edition Kalbfleisch Probability and Statistical Inference: Volume 2: Statistical Inference. Second Edition Keyfitz Applied Mathematical Demography. Second Edition Kiefer Introduction to Statistical Inference Kokoska and Nevison Statistical Tables and Formulae Madansky Prescriptions for Working Statisticians McPherson Statistics in Scientific Investigation: Basis, Application, and Interpretation Nguyen and Rogers Fundamentals of Mathematical Statistics: Volume I: Probability for Statistics Nguyen and Rogers Fundamentals of Mathematical Statistics: Volume II: Statistical Inference Peters Counting for Something: Statistical Principles and Personalities (continued after index) Glen McPherson Statistics in Scientific Investigation Its Basis, Application, and Interpretation With 58 Illustrations Springer Science+Business Media, LLC Glen McPherson Department of Mathematics The University of Tasmania Hobart, Tasmania 7001 Australia E-Mail Address: [email protected] Editorial Board Stephen Fienberg Ingram Olkin Department of Statistics Department of Statistics Carnegie-Mellon University Stanford University Pittsburgh, PA 15213 Stanford, CA 94305 USA USA Mathematics Subject Classification (1980): 62-01, 62-07, 62PIO, 62P15, 62P25 McPherson, Glen. Statistics in scientific investigation : its basis, application, and interpretation I Glen McPherson. p. em. - (Springer texts in statistics) I. Research-Statistical methods. 2. Science-Statistical methods. 3. Statistics. I. Title. II. Series. Q180.55.S7M36 1990 507.2-{!c20 89-21711 Printed on acid-free paper. © 1990 Springer Science+ Business Media New York Originally published by Springer-Verlag New York, Inc. in 1990 Softcover reprint of the hardcover 1st edition 1990 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher, Springer Science+Business Media, LLC, except for brief excerpts in except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software,or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use of general descriptive names, trade names, trademarks, etc., in this publication, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone. Camera-ready copy prepared using LaTEX· 9 8 7 6 5 4 3 2 I ISBN 978-1-4757-4292-3 ISBN 978-1-4757-4290-9 (eBook) DOI 10.1007/978-l-4757-4290-9 Affectionately dedicated to my family, Wendy, Ewen, and Meegan Contents Preface Xlll Plan of the Book XVll Using the Book XXl Commonly Used Symbols XXV 1 The Role of Statistics in Scientific Investigation 1 1.1 Scientific Investigation 1 1.2 Statistics in the Experimental Process 2 1.3 Descriptive Statistics 10 1.4 Analytic Statistics 27 Problems 29 2 Data: The Factual Information 34 2.1 Data Collection 34 2.2 Types of Data 40 Problems 43 3 Statistical Models: The Experimenter's View 46 3.1 Components of a Model 46 3.2 Hypotheses 47 3.3 Sampling Assumptions 54 3.4 Statistical Assumptions 56 Problems 57 4 Comparing Model and Data 60 4.1 Intuitive Ideas 60 4.2 The Role of Statistics 64 4.3 Measuring Agreement Between Model and Data 65 viii Contents 5 Probability: A Fundamental Tool of Statistics 73 5.1 Probability and Statistics 73 5.2 Sampling Distributions 75 5.3 Probability: Definitions and Rules 82 5.4 Random Variables 84 Appendix: Combinatorial Formulae 94 Problems 95 6 Some Widely Used Statistical Models 100 6.1 The Binomial Model 100 6.2 The Two-State Population Model 101 6.3 A Model for Occurrences of Events 103 6.4 The Multinomial Model 105 6.5 The Normal Distribution Model 107 6.6 The Logistic Model 114 Problems 119 7 Some Important Statistics and Their Sampling Distributions 122 7.1 The Binomial Distribution 122 7.2 The Poisson Distribution 127 7.3 The Normal Distribution 128 7.4 The t-Distribution 133 7.5 The Chi-Squared Distribution 137 7.6 The F-Distribution 138 7.7 Statistics Based on Signs and Ranks 140 7.8 Statistics Based on Permutations 145 Problems 149 8 Statistical Analysis: The Statisticians' View 154 8.1 The Range in Models and Approaches 154 8.2 Hypothesis Testing 156 8.3 Estimation 162 8.4 Likelihood 169 8.5 The Bayesian Approach 170 8.6 Choosing the Best Method 175 Problems 177 9 Examining Proportions and Success Rates 181 9.1 Experimental Aims 181 Contents lX 9.2 Statistical Analysis 185 Problems 195 10 Model and Data Checking 199 10.1 Sources of Error in Models and Data 199 10.2 Detecting Errors in Statistical Models 201 10.3 Analyzing Residuals 206 10.4 Checking Data 218 10.5 Data Modification or Method Modification? 221 Problems 223 11 Questions About the "Average" Value 227 11.1 Experimental Considerations 227 11.2 Choosing and Applying Statistical Methods 230 Problems 240 12 Comparing Two Groups, Treatments or Processes 242 12.1 Forms of Comparison 242 12.2 Comparisons Based on Success Rates and Proportions 248 12.3 Comparisons of Means 260 12.4 Comparisons of Medians 274 12.5 A Consideration of Rare Events 283 Problems 289 13 Observational Studies, Surveys and Designed Experiments 297 13.1 Observational Study or Designed Experiment? 297 13.2 Experimental and Treatment Designs 301 13.3 Paired Comparisons 309 13.4 Surveys 318 Appendix 1: Steps in Randomly Selecting a Sample from a Population 328 Appendix 2: Steps in Random Allocation of Units Between Treatments 329 Problems 330 14 Comparing More Than Two Treatments or Groups 332 14.1 Approaches to Analysis 332 X Contents 14.2 Statistical Models 345 14.3 Statistical Methods 352 14.4 Practical Considerations 360 14.5 Comparisons Based on Medians 363 Problems 368 15 Comparing Mean Response When There Are Three or More Treatments 371 15.1 Experimental and Statistical Aims 371 15.2 Defining and Choosing Designs 371 15.3 Model and Data Checking 394 15.4 Analysis of Variance and One-Stratum Designs 403 15.5 Tw<rStrata Designs 408 15.6 More Complex Designs 417 15.7 Factorial Arrangement of Treatments 423 15.8 More Detailed Comparison of Treatment Differences 434 Problems 442 16 Comparing Patterns of Response: Frequency Tables 446 16.1 The Scope of Applications 446 16.2 Statistical Models and Methodology 451 Problems 473 17 Studying Association and Correlation 475 17.1 Relations Between Two Categorical Variables 475 17.2 Relations Between Two Scaled Variables 481 17.3 Relations Between Three or More Categorical Variables 497 17.4 Relations Between Three or More Scaled Variables 501 Problems 506 18 Prediction and Estimation: The Role of Explanatory Variables 509 18.1 Regression Analysis 509 18.2 Statistical Models 516 18.3 Statistical Methods 519 18.4 Practical Considerations 528 18.5 Statistical Analysis 532 18.6 Applications of Regression Analysis 537 18.7 Experimental Design and Regression Analysis 554 Problems 562 Contents xi 19 Questions About Variability 568 19.1 Variability-Its Measurement and Application 568 19.2 Variance Components 575 Problems 587 20 Cause and Effect: Statistical Perspectives 589 20.1 The Allocation of Causality: Scientific Aims and Statistical Approaches 589 20.2 Statistical Methods in Use 592 21 Studying Change in Response over Time 596 21.1 Applications 596 21.2 Time Series 599 21.3 Time Series: Statistical Models and Methods 606 22 Computers and Statistics 613 22.1 The Role of Computers in Statistics 613 22.2 Using Computers-Practical Considerations 615 22.3 Statistical Packages 616 22.4 Choosing a Computer 621 Appendix A: Tables for Some Common Probability Distributions 622 References 645 Figure, Table, and Example Index 647 Index 653