UNDERSTANDING AND USING ADVANCED STATISTICS Jeremy J Foster Emma Barkus Christian Yavorsky 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page i UNDERSTANDING AND USING ADVANCED STATISTICS 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page ii 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page iii UNDERSTANDING AND USING ADVANCED STATISTICS Jeremy Foster Emma Barkus Christian Yavorsky SAGE Publications London ●Thousand Oaks ● New Delhi 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page iv © Jeremy Foster,Emma Barkus,Christian Yavorsky 2006 First published 2006 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 1 Oliver’s Yard 55 City Road London EC1Y 1SP SAGE Publications Inc. 2455 Teller Road Thousand Oaks,California 91320 SAGE Publications India Pvt Ltd B-42,Panchsheel Enclave Post Box 4109 New Delhi 110 017 BBrriittiisshh LLiibbrraarryy CCaattaalloogguuiinngg iinn PPuubblliiccaattiioonn ddaattaa A catalogue record for this book is available from the British Library ISBN 1 4129 0013 1 ISBN 1 4129 0014 X (pbk) LLiibbrraarryy ooff CCoonnggrreessss CCoonnttrrooll NNuummbbeerr:: 22000055992299118800 Typeset by C&M Digitals (P) Ltd,Chennai,India Printed on paper from sustainable resources Printed in Great Britain by The Cromwell Press Ltd,Trowbridge,Wiltshire 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page v Summary of Contents 1 Basic features of statistical analysis and the general linear model 1 2 Multivariate analysis of variance 16 3 Multiple regression 30 4 Log–linear analysis 47 5 Logistic regression 57 6 Factor analysis 70 7 Path analysis 89 8 Structural equation modelling 103 9 Time series analysis 115 10 Facet theory and smallest space analysis 130 11 Survival or failure analysis 145 12 Repertory grids 156 Index 173 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page vi 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page vii Contents 11 BBaassiicc ffeeaattuurreess ooff ssttaattiissttiiccaall aannaallyyssiiss aanndd tthhee ggeenneerraall lliinneeaarr mmooddeell 11 Introduction 1 Basic features of statistical analysis 2 Experiments or correlational research designs 2 Independent and dependent variables 2 Types of data 3 Non-parametric and parametric analyses 4 Statistical significance 6 Recapitulation of analysis of variance (ANOVA) 7 Main effects,simple effects,interaction 8 The general linear model 10 When do you need the GLM? 11 Summary 13 Glossary 14 References 14 Further reading 14 Internet sources 15 22 MMuullttiivvaarriiaattee aannaallyyssiiss ooff vvaarriiaannccee 1166 What multivariate analysis of variance is 16 When do you need MANOVA? 16 What kinds of data are necessary? 16 How much data? 17 Example of MANOVA 17 What a MANOVA does 19 Example of output of SPSS 22 Example of the use of MANOVA 26 From health 26 FAQs 27 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page viii viii • CONTENTS Summary 28 Glossary 28 References 28 Further reading 29 Internet sources 29 33 MMuullttiippllee rreeggrreessssiioonn 3300 What multiple regression is 30 When do you need multiple regression? 30 Words of warning 31 Recapitulation of correlation and regression 31 Recapitulation of partial correlation 32 The regression equation in multiple regression 33 What kinds of data are needed? 35 How much data? (How many respondents for how many independent variables?) 35 Which independent variables to include? 36 Technical considerations and screening the data 36 Outliers 36 Muticollinearity 37 Normally distributed,linearly related,homoscedastic? 38 How do you do multiple regression? 39 Cross-validation 41 Interactions 41 Examples of multiple regression and its interpretation 42 From psychology 42 From health 42 From business/management 43 FAQs 44 Summary 44 Glossary 45 References 45 44 LLoogg––lliinneeaarr aannaallyyssiiss 4477 What log–linear analysis is 47 Recapitulation of contingency tables 47 When do you need log–linear analysis? 49 What kinds of data are needed? 49 How much data? 49 How to do log–linear analysis 49 Examples from psychology,health and business 52 00-Foster-3327(Prelims).qxd 10/12/2005 12:13 PM Page ix Contents • ix From psychology 52 From health 54 From business 54 FAQs 55 Summary 55 Glossary 56 References 56 Further reading 56 55 LLooggiissttiicc rreeggrreessssiioonn 5577 What logistic regression is 57 When do you need logistic regression? 57 Different types of logistic regression 59 What kinds of data are needed? 62 How much data? (How many respondents for how many independent variables?) 62 Which independent variables to include? 62 Technical considerations and screening the data 62 How do you do logistic regression? 63 Limitations of logistic regression 63 Example of logistic regression and its interpretation 64 Examples of the use of logistic regression 67 From psychology 67 From health 68 FAQs 68 Summary 68 Glossary 69 References 69 Further reading 69 Internet source 69 66 FFaaccttoorr aannaallyyssiiss 7700 What factor analysis is 70 When do you need factor analysis? 70 Principal components analysis and factor analysis 71 What kinds of data are needed? 72 How much data? (How many respondents for how many independent variables?) 73 How many variables to include? 74 Which variables to include? 74 Technical considerations and screening the data 75