Note to Instructor Notes to instructors are included in the margin throughout this text, but they are not included in student editions. As we proceed through this chapter and discuss types of data and sampling methods, we should focus on these key concepts: When we want to use sample data to learn something about a population, it is extremely important to obtain sample data that are representative of the population from which the data are drawn. The large number of respondents does not overcome this flaw of having a voluntary response sample. With a voluntary response sample, it often happens that those with a strong interest in the topic are more likely to participate, so the results are very questionable. This is an example of a voluntary response sample-a sample in which respondents decide themselves whether to participate. The survey question was posted on the America OnLine Web site and Internet users decided whether to respond. Thus Figure 1 makes it appear that the “yes” responses are about three times the number of “no” responses, but examination of the actual response counts shows that the “yes” responses are really about 1.7 times the “no” responses.įlaw 2: Bad Sampling Method The survey responses are from a recent America OnLine survey of Internet users. Using a vertical scale that does not startĪt zero exaggerates the difference between the two numbers of responses. Following are brief descriptions of each of the two major flaws.įigure 1 is deceptive. Because these two flaws are among the most common, it is especially important to recognize them. Who conducted the survey? How were respondents selected? Does the graph in Figure 1 depict the results in a way that is not misleading? The survey results presented here have two major flaws. We might question whether the survey results are valid. One important objective of this text is to encourage the use of critical thinking so that such results are not blindly accepted. That roughly three times as many respondents have been hit by computer viruses as have notġ70,063 adults, and that is a very large number of respondents. Also, by looking at the bars in Figure 1, we see One thousand or two thousand respondents. The results of the survey appear to be quite dramatic. (Figure 1 was generated using Minitab statistical software.) “Have you ever been hit by a computer virus?” The survey question and responses are given below, and Figure 1 graphically depicts the survey results. Let’s consider one particular survey dealing with a topic of great concern to all of us who have embraced the use of computer technology. Surveys provide us with understanding about the thinking of the rest of the world. Surveys shape business practices and many other aspects of our lives. Surveys determine what television shows we watch. Surveys are essential tools used in marketing. The world in which we live is now saturated with surveys. Survey: Have you ever been hit with a computer virus? Copyright © 2014 by Pearson Education, Inc. Triolaįrom Chapter 1 of Elementary Statistics Using Excel, 5th Edition.

Goodness-of-Fit and Contingency Tables Mario F. Normal Probability Distributions Mario F.

Discrete Probability Distributions Mario F. Statistics for Describing, Exploring, and Comparing Data Mario F. ISBN 10: 6-5 ISBN 10: 0-8 ISBN 13: 978-6-6 ISBN 13: 978-0-7īritish Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library Printed in the United States of America The use of any trademark in this text does not vest in the author or publisher any trademark ownership rights in such trademarks, nor does the use of such trademarks imply any afﬁliation with or endorsement of this book by such owners. All trademarks used herein are the property of their respective owners. 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 or otherwise, without either the prior written permission of the publisher or a licence permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, Saffron House, 6–10 Kirby Street, London EC1N 8TS. Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world Visit us on the World Wide Web at: © Pearson Education Limited 2014 All rights reserved. Pearson New International Edition Elementary Statistics Using Excel Mario F. Elementary Statistics Using Excel Triola 5eĮlementary Statistics Using Excel Mario F.

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