Understanding and Using Statistics in Psychology: A Practical Introduction

365 Pages·2007·3.617 MB·English

by  Jeremy Miles, Philip Banyard

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Understanding and Using
Statistics in Psychology
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Understanding and Using
Statistics in Psychology
A Practical Introduction
or, how I came to know and love the standard error
Jeremy Miles and Philip Banyard
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© Jeremy Miles and Philip Banyard 2007
First published 2007
Apart from any fair dealing for the purposes of research or private
study,or criticism or review,as permitted under the Copyright,
Designs and Patents Act,1988,this publication may be reproduced,
stored or transmitted in any form,or by any means,only with the
prior permission in writing of the publishers,or in the case of
reprographic reproduction,in accordance with the terms of licences
issued by the Copyright Licensing Agency. Enquiries concerning
reproduction outside those terms should be sent to the publishers.
SAGE Publications Ltd
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Library of Congress Control Number:2006929861
British Library Cataloguing in Publication data
A catalogue record for this book is available from the British Library
ISBN 978-0-7619-4396-9
ISBN 978-0-7619-4397-6 (pbk)
Typeset by C&M Digitals (P) Ltd, Chennai, India
Printed in Great Britain by The Alden Press, Witney
Printed on paper from sustainable resources
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Contents
Acknowledgements vii
1 Introduction:How to get started with statistics 1
2 Descriptive statistics 11
3 Samples,populations and the normal distribution 52
4 Making inferences:confidence limits and statistical significance 80
5 Analysing data from repeated measures experiments 106
6 Analysing data from independent groups:continuous ordinal measures 135
7 Analysing data from independent groups:categorical measures 169
8 Relationships between variables:correlation and regression 194
9 Introducing analysis of variance 237
10 Analysing questionnaires and measurement instruments 269
11 Thinking some more about statistics 300
12 Report writing 321
Appendices 335
References 344
Index 351
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Acknowledgements
We would like to acknowledge the support of our colleagues in the Psychology Division
at Nottingham Trent University and the Health Sciences Department at the University of
York who provide a positive and friendly working environment. We would also like to
thank the many people who commented on the drafts and so helped in the development of
this text. If we are successful in selling the film rights we promise to give them all a walk-
on part. We would also like to acknowledge the support and indulgence of Michael
Carmichael and Claire Reeve at Sage (and we promised not to mention the thumbscrews).
They can be in the film as well if they like.
We would like to give name checks (in no particular order) to Nick Neave,(University
of Northumbria at Newcastle), Peter White (Southampton University), Keith Bender
(Royal Perth Hospital),Linden Ball (University of Lancaster),James Roney (University of
California, Santa Barbara), Barry Wright (Selby and York Primary Care Trust), Charles
Hulme (University of York),Mark Torrance (Staffordshire University) and Martin Dorahy
(Queen's University,Belfast) for allowing us to use and abuse their painstakingly collected
data.
Jeremy would like to thank Susanne,Alex and Daniel for allowing him to spend hours
at a computer writing this text and generally ignoring them. Phil would like to thank Mark
Shevlin whose reluctance to tear himself away from the bookies and collaborate with
Jeremy gave him the opportunity to be the support act on this text. Phil would also like to
give name checks to the darts players of the Gladstone in Carrington,the loyal supporters
of Nottingham Forest and to Jeremy for writing most of this and not laughing at him when
he didn’t understand something.
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1
Introduction: how to get
started with statistics
WWhhaatt’’ss iinn tthhiiss cchhaapptteerr??
• The misuse of statistics
• Computers and statistics
• How to use this text
• Which chapter do you want?
IINNTTRROODDUUCCTTIIOONN
This chapter explains why we need statistics and why you should love them. It explains
why it is important to understand statistics,which is principally so that we don’t get fooled
by numbers. It also provides a guide to how this book is best used. We realise that most
readers will go to the chapter that best suits their immediate needs and are only reading
this if it is the last book in their bag and their train has been indefinitely delayed. If you
are this position then we hope it gets better soon.
SSTTUUDDYYIINNGG SSTTAATTIISSTTIICCSS IISS GGRREEAATT
This heading is not an indication of madness on the part of the authors. Statistics really is
great and it is a remarkable observation that when students finish their statistics courses after