Introductory Statistics

© Courtney Keating/iStockphoto Eighth Edition INTRODUCTORY STATISTICS PREM S. MANN EASTERN CONNECTICUT STATE UNIVERSITY WITH CONTRIBUTIONS BY CHRISTOPHER JAY LACKE ROWAN UNIVERSITY Vice President and Executive Publisher Laurie Rosatone Acquisitions Editor Joanna Dingle Project Editor Ellen Keohane Associate Content Editor Beth Pearson Editorial Program Assistant Liz Baird Senior Content Manager Karoline Luciano Senior Production Editor Kerry Weinstein Production Management Services Aptara, Inc. Photo Editor Lisa Gee Marketing Manager Melanie Kurkjian Senior Designer Madelyn Lesure Senior Product Designer Thomas Kulesa Editorial Operations Manager Melissa Edwards Media Production Specialist Laura Abrams Cover Designer Madelyn Lesure Cover photo: © Lawrence Manning/Age Fotostock America, Inc. This book was set in 10/12 Times Roman by Aptara®, Inc. and printed and bound by Courier-Kendallville. The cover was printed by Courier-Kendallville. This book is printed on acid free paper. ⬁ Copyright © 2013, 2010, 2007, 2004, 2001, John Wiley & Sons, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc. 222 Rosewood Drive, Danvers, MA 01923, website www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030-5774, (201)748-6011, fax (201)748-6008, website http://www.wiley.com/go/permissions. Evaluation copies are provided to qualified academics and professionals for review purposes only, for use in their courses during the next academic year. These copies are licensed and may not be sold or transferred to a third party. Upon completion of the review period, please return the evaluation copy to Wiley. Return instructions and a free of charge return shipping label are available at www.wiley.com/go/returnlabel. Outside of the United States, please contact your local representative. Library of Congress Cataloging in Publication Data ISBN 978-0-470-90410-7 (cloth) ISBN 978-1-118-17224-7 (Binder Ready Version ) Printed in the United States of America 10 9 8 7 6 5 4 3 2 1 To the memory of my parents PREFACE Introductory Statistics is written for a one- or two-semester first course in applied statistics. This book is intended for students who do not have a strong background in mathematics. The only prerequisite for this text is knowledge of elementary algebra. Today, college students from almost all fields of study are required to take at least one course in statistics. Consequently, the study of statistical methods has taken on a prominent role in the education of students from a variety of backgrounds and academic pursuits. From the first edition, the goal of Introductory Statistics has been to make the subject of statistics interesting and accessible to a wide and varied audience. Three major elements of this text support this goal: 1. 2. 3. Realistic content of its examples and exercises, drawing from a compr