Selecting a Descriptive Statistical Procedure Type of Data Individual Scores Central Tendency Variability Correlation Coefficient Nominal frequency, rel frequency, or percent (Chapter 3) Mode (Chapter 4) Range (Chapter 5) or C (Chapter 15) Ordinal frequency, rel frequency, or percent (Chapter 3) Median (Chapter 4) Range (Chapter 5) Spearman rS (Chapter 7) Interval or ratio (skewed distribution) frequency, rel frequency, or percent (Chapter 3) Median (Chapter 4) Range (Chapter 5) Convert to ranks, compute Spearman rS (Chapter 7) Interval or ratio (normally distributed) frequency, rel frequency, percent, or z-score (Chapters and 6) Mean (Chapter 4) Standard deviation or variance (Chapter 5) Pearson r (Chapter 7) and regression (Chapter 8) Selecting an Inferential Statistical Procedure Type of Design Parametric Test Nonparametric Test One sample (when σX is known) One sample (when σX is not known) z-test (Chapter 10) One-sample t-test (Chapter 11) none Two independent samples Independent samples t-test (Chapter 12) Mann–Whitney U, rank sums test, or one-way chi square (Chapter 15) Two related samples Related samples t-test (Chapter 12) Wilcoxon T test (Chapter 15) Three or more independent samples (one factor) Between-subjects ANOVA Post Hoc test: HSD or protected t-test (Chapter 13) Kruskal–Wallis H or one-way chi square Post Hoc test: rank sums test (Chapter 15) Three or more related samples (one factor) Within-subjects ANOVA Post Hoc test: HSD or protected t-test (Appendix A) Friedman 2 Post Hoc test: Nemenyi’s test (Chapter 15) Two factors (independent samples) Two-way, between-subjects ANOVA (Chapter 14) Two-way chi square (Chapter 15) none SIX SIXTH TH EDITION EDITION Basic Statistics for the Behavioral Sciences This page intentionally left blank SIX SIXTH TH EDITION EDITION Basic Statistics for the Behavioral Sciences Gary W Heiman Buffalo State College Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States Basic Statistics for the Behavioral Sciences, Sixth Edition Gary W Heiman Executive Editor: Jon-David Hague Assistant Editor: Rebecca Rosenberg Editorial Assistant: Alicia McLaughlin Media Editor: Mary Noel Marketing Manager: Kim Russell Marketing Assistant: Anna Andersen Marketing Communications Manager: Talia Wise Content Project Manager: Charlene M Carpentier © 2011, 2006 Wadsworth, Cengage Learning ALL RIGHTS RESERVED No part of this work covered by the copyright herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, Web distribution, information networks, or information storage and retrieval systems, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the publisher For product information and technology assistance, contact us at Cengage Learning Customer & Sales Support, 1-800-354-9706 For permission to use material from this text or product, submit all requests online at www.cengage.com/permissions Further permissions questions can be e-mailed to permissionrequest@cengage.com Creative Director: Rob Hugel Art Director: Vernon Boes Library of Congress Control Number: 2009936829 Print Buyer: Karen Hunt Student Edition: Rights Acquisitions Account Manager, Text: Bob Kauser ISBN-13: 978-0-8400-3143-3 ISBN-10: 0-8400-3143-2 Rights Acquisitions Account Manager, Image: Robyn Young Advantage Edition Production Service: PrePressPMG ISBN-13: 978-0-495-90994-1 Text Designer: Lisa Henry ISBN-10: 0-495-90994-7 Illustrator: PrePressPMG Cover Designer: Denise Davidson Cover Image: John Foxx/Getty Images Compositor: PrePressPMG Wadsworth 20 Davis Drive Belmont, CA 94002-3098 USA Cengage Learning is a leading provider of customized learning solutions with office locations around the globe, including Singapore, the United Kingdom, Australia, Mexico, Brazil, and Japan Locate your local office at www.cengage.com/global Cengage Learning products are represented in Canada by Nelson Education, Ltd To learn more about Wadsworth, visit www.cengage.com/Wadsworth Purchase any of our products at your local college store or at our preferred online store www.ichapters.com Printed in Canada 13 12 11 10 09 For my wife, Karen, the love of my life This page intentionally left blank BRIEF CONTENTS PREFACE xxii Introduction to Statistics Statistics and the Research Process 12 Frequency Distributions and Percentiles 36 Measures of Central Tendency: The Mean, Median, and Mode 60 Measures of Variability: Range, Variance, and Standard Deviation 84 10 11 z-Scores and the Normal Curve Model 109 12 13 14 15 The Two-Sample t-Test 260 Correlation Coefficients 135 Linear Regression 160 Using Probability to Make Decisions about Data Introduction to Hypothesis Testing 185 207 Performing the One-Sample t-Test and Testing Correlation Coefficients 234 The One-Way Analysis of Variance 290 The Two-Way Analysis of Variance 318 Chi Square and Other Nonparametric Procedures 351 APPENDIXES A B C D Additional Statistical Formulas 379 Using SPSS 392 Statistical Tables 418 Answers to Odd-Numbered Questions 438 GLOSSARY INDEX 453 461 vii ... Statistical Hypotheses for the Independent-Samples t-Test 262 The Sampling Distribution for the Independent-Samples t-Test 263 Computing the Independent-Samples t-Test 264 Estimating the Population... the Related-Samples t-Test 272 STATISTICAL HYPOTHESES FOR THE RELATED-SAMPLES t-TEST 273 Computing the Related-Samples t-Test 274 Interpreting the Related-Samples t-Test 275 Computing the Confidence... ABOUT t-TESTS? 234 PERFORMING THE ONE-SAMPLE t-TEST 235 Computing tobt 236 A QUICK REVIEW 237 The t-Distribution and Degrees of Freedom 238 Using the t-Tables 240 Interpreting the t-Test 240 The