Research Methods and Statistics in Psychology

Research Methods and Statistics in Psychology......Page 2
Copyright......Page 3
Contents......Page 6
Preface......Page 9
Why psychology and science?......Page 12
Science – not a subject but a way of thinking......Page 15
So what is this scientific method then?......Page 19
Asking why? Generating theories for laws......Page 21
The hypothetico-deductive method – testing scientific theories......Page 22
How psychologists actually do scientific research......Page 28
What are the main features of a psychological investigation?......Page 30
Qualitative data and qualitative approaches......Page 36
Variables......Page 39
Operational definitions of psychological constructs......Page 44
Reliability and validity......Page 47
Samples......Page 49
Probability based sampling methods......Page 54
Non-probability-based sampling methods (non-epsem)......Page 56
Purposive sampling......Page 57
Introducing the qualitative/quantitative debate......Page 59
The role of experiments in gathering evidence – demonstrating cause and effect......Page 67
Alternative explanations......Page 68
Features of the true experiment; avoiding confounds......Page 70
The independent samples design......Page 77
Repeated measures design......Page 79
Matched-pairs design......Page 84
Single participant or small n design......Page 85
4 Validity in psychological research......Page 92
Sources of variance in the experiment......Page 93
Validity in experiments and other research designs......Page 95
Internal validity......Page 97
Construct validity and the problem of confounding variables......Page 99
Tackling confounds – the heart of science?......Page 100
Expectancy and the social psychology of the psychology experiment......Page 103
External validity......Page 108
Meta-analysis......Page 111
The field and the laboratory......Page 117
True experiments and field experiments......Page 118
Non-equivalent groups......Page 119
Control and validity in the laboratory and in the field......Page 126
Observation in general......Page 134
Observation as a technique or as an overall design......Page 135
Controlled observation......Page 140
Qualitative non-participant observation......Page 143
Role-play and simulation......Page 144
The diary method......Page 145
Participant observation......Page 148
Case studies......Page 153
Indirect observation......Page 157
Introduction – Self-report methods......Page 161
Structured interviews......Page 162
Effects of interpersonal variables in interviews......Page 163
Types of interview......Page 166
Semi-structured or open interviewing – gathering qualitative data......Page 169
Surveys......Page 176
8 Psychological tests and measurement scales......Page 183
Measurement vs. information gathering: scales, tests, inventories and questionnaires......Page 184
Open and closed questions......Page 185
Attitude scales......Page 188
Central issues in the use of psychological scales......Page 193
Scale items – what to avoid in statement construction......Page 195
Projective tests......Page 198
Intelligence and personality tests......Page 199
Reliability, validity and standardisation......Page 205
9 Comparison studies – cross-sectional, longitudinal and cross-cultural studies......Page 217
Cross-sectional studies......Page 218
Longitudinal studies......Page 219
Evaluation of longitudinal and cross-sectional studies......Page 221
Cross-cultural studies......Page 223
10 Qualitative approaches in psychology......Page 233
Psychology and the positivist paradigm......Page 234
The problem with quantification in psychological research......Page 236
Qualitative data gathering......Page 241
Grounded theory......Page 242
Interpretive phenomenological analysis (IPA)......Page 244
Discourse analysis (DA)......Page 245
Thematic analysis......Page 247
Action research......Page 249
Memories as narratives......Page 250
A feminist perspective......Page 252
Contemporary qualitative methods......Page 254
Measuring things......Page 258
A quick introduction to different levels of measurement......Page 261
Summarising data – statistics are a selection......Page 272
Measures of central tendency......Page 274
Measures of dispersion......Page 279
Population parameters, sample statistics and sampling error......Page 285
Using SPSS to calculate statistics......Page 286
Appendix – Statistical notation and symbols......Page 296
Graphs in general......Page 298
The bar chart......Page 299
Line charts......Page 302
The histogram......Page 303
Exploratory data analysis......Page 305
Using SPSS to produce your charts......Page 309
Dealing with larger data sets......Page 316
The normal distribution......Page 319
Z scores (or ‘standard scores’)......Page 323
Standardisation of psychological measurements......Page 325
Sampling distributions......Page 326
Confidence intervals......Page 327
Skewed distributions......Page 328
Kurtosis in distributions......Page 329
14 Significance testing – was it a real effect?......Page 333
Significance decisions......Page 334
The null and alternative hypotheses – working in the glove department......Page 336
Probability......Page 337
How low is low? Rejecting the null hypothesis......Page 341
The standard level of significance – p ≤ .05 or the ‘5% significance level’......Page 343
Critical values......Page 344
Significance testing – the basic model and a concrete example......Page 345
Rejection regions (and the peculiar effects of spinach)......Page 348
But couldn’t this just be a fluke? Type I errors......Page 349
The question of power and effect size......Page 352
Significance ‘levels’......Page 353
Directional and non-directional hypotheses – one-tailed and two-tailed tests......Page 354
15 Testing for differences between two samples......Page 361
The t test for related data......Page 362
The t test for unrelated data......Page 369
The single sample t test......Page 373
Data assumptions for t tests......Page 374
The Wilcoxon (T) matched pairs signed ranks test......Page 379
SPSS procedures for two condition difference tests......Page 390
Effect size and power: when ‘significant’ is not significant......Page 396
Tests on two-way frequency tables......Page 408
Unrelated data – the Chi-square test of association......Page 410
The 2 x 2 chi-square......Page 413
More complex chi-square data (r x c designs)......Page 419
The ‘goodness of fit’ test –
x2 on a single variable......Page 420
SPSS procedure for conducting a r x c chi-square test......Page 421
Multi-way frequency tables and loglinear analysis......Page 427
Conducting a three-way driving analysis in SPSS......Page 433
17 Correlation......Page 439
Simple correlation......Page 440
Measurement of a correlation......Page 443
Pearson’s product-moment correlation coefficient – interval level data......Page 449
Significance and correlation coefficients......Page 457
Variance estimates – r2......Page 460
SPSS procedures for correlation......Page 461
What you can’t assume with a correlation......Page 463
Correlation when one variable is categorical......Page 466
Common uses of correlation in psychology......Page 468
Regression and multiple regression......Page 472
Multiple predictions......Page 474
Partial and semi-partial correlation......Page 476
Regression coefficients......Page 477
Effect size and power......Page 478
Conducting and reporting a multiple regression analysis in SPSS......Page 479
18 Multi-level analysis – differences between more than two conditions......Page 486
Introduction to more complex tests......Page 487
One-way ANOVA – unrelated designs......Page 488
The F ratio statistic......Page 493
Effect size......Page 496
A priori and post hoc comparisons......Page 497
Estimating power in one-way ANOVA......Page 502
Non-parametric ANOVA equivalent – the Kruskal–Wallis one-way analysis of variance......Page 503
Multivariate Analysis of Variance (MANOVA)......Page 505
SPSS procedures for one-way ANOVA......Page 506
Kruskal-Wallis in SPSS......Page 508
Using two or more independent variables......Page 512
Interaction effects......Page 514
The camouflage of main effects......Page 515
Simple effects......Page 517
Three-way ANOVA calculation......Page 523
SPSS procedure for two-way between groups ANOVA......Page 524
Related designs......Page 529
Between subjects and between conditions variation......Page 531
Data assumptions for repeated measures ANOVA......Page 534
Two-way (related) design......Page 535
ANOVA mixed design – one repeated measure

and one unrelated factor......Page 538
More complex ANOVA designs......Page 540
A non-parametric equivalent – the Friedman test

for correlated samples......Page 541
SPSS procedures for repeated measures ANOVA......Page 543
Choosing an appropriate test......Page 551
Tests for two samples......Page 552
Tests for more than two samples......Page 558
Computers and the internet......Page 559
Quantitative analysis of qualitative data – Content analysis......Page 565
Qualitative content analysis......Page 568
Doing qualitative research......Page 569
Considerations for a qualitative project......Page 573
Data analysis......Page 576
Procedures in major approaches......Page 577
Grounded theory (GT)......Page 578
Interpretive Phenomenological Analysis (IPA)......Page 579
Discourse analysis (DA)......Page 580
Writing up the report......Page 582
Reliability and validity – how are qualitative studies evaluated?......Page 585
Introduction......Page 596
Publication and access to data......Page 598
The conduct of research with human participants......Page 600
Research with animals......Page 608
Conclusion......Page 611
Planning your practical project......Page 614
The overall aim......Page 615
The design......Page 616
The sample(s)......Page 618
The materials......Page 619
The procedure......Page 620
Ethics......Page 621
Writing your practical report......Page 622
Comments on a student practical report......Page 638
A better report of the same practical......Page 646
Appendix to Chapter 22......Page 652
Appendix......Page 661
References......Page 682
Index......Page 700