How to Design and Report Experiments
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Mode, 115
Model mean of squared errors (MSM), see Mean of squared errors
Model sum of squares (SSM), see Sum of squared errors
Multi-factorial designs, 86–8
Multimodal distribution, 115
Multivariate, 50
Negative skew, see Skew
Nominal data, 6, 266
See also Levels of measurement, Measurement
Nonparametric tests, 8, 43, 162, 176, 234–57, 268–9
See also Friedman’s ANOVA, Kruskal-Wallis test, Mann-Whitney test, Wilcoxon signed-rank test
Normal distribution, 113, 160
Null hypothesis, 141–2, 145, 149, 150–1
Observational method, 3, 64–5,
Advantages of, 65
Disadvantages of, 65
Omega-squared (ω2), 181, 190, 199–200, 211, 221, 230
See also Effect size
One-tailed test, 155
One-way independent ANOVA, 174–83, 224
Assumptions, see Homogeneity of variance
And reporting results, 181–3
And SPSS, 175–80
When to use, 174
See also Effect size
One-way repeated measures ANOVA, 183–91, 224
Assumptions, see Sphericity
And reporting results, 190–1
And SPSS,185–9
When to use, 183
See also Effect size
Ordinal data, 7–8, 266
see also Levels of measurement, Measurement
Outliers, 118, 121, 237
Paradigm, 27
Paradigm shift, 27–9
Parametric tests, 8, 43, 159–233, 268–9
See also Analysis of Covariance, Analysis of Variance, t-Test
Participants, 62–3,
Volunteer characteristics, 62
Planned comparisons, 173, 219–20
See also Repeated contrast
Platykurtic, see Kurtosis
Population, 109
Positive skew, see Skew
Post hoc tests, 173, 178, 182, 188–9, 191, 208, 217, 219, 247, 252
Gabriel’s test, 178
Games-Howell test, 178–9, 182–3, 199, 201
Hochberg’s GT2, 178–9
REGWQ, 178, 179–80
Tukey HSD, 178
See also Bonferroni correction
Power, 154–7
And sample size, 156
Calculating, 154, 156
Psyclit, see Databases
Psylnfo, see Databases
Quasi-experimental designs, 66–70,
Definition of quasi-experimental, 66,
Problems associated with, 66–8
Types of, 68–70
Q-Q plot, 162
r, 148, 153, 166
r2 (the coefficient of determination), 148
Randomization, 24, 71
Ratio data, 9, 267
See also Levels of measurement, Measurement
Reaction times, 9, 44
Referencing,
Conventions for, 345–56
Example reference section, 371–2
Primary and secondary references, 355–6
Regression to the mean, 58
REGWQ, see Post hoc tests
Related t-test, see t-Test
Reliability, 47–8
Alternate form, 47–8
Cronbach’s alpha, 48
Maximizing, 58
Split-half, 48
Test-retest, 47
Repeated contrast, 219
Repeated measures designs, 79–82,
Advantages of, 79–80,
Disadvantages of, 80–2
Replication, 26
Report-writing,
Abstract, 289, 344–7, 360–1
Apparatus section, 292, 322–3
Checklist of things to include, 299–300
Conclusion, 342
Describing previous research, 313–15
Design section, 291, 320–1, 364
Discussion section, 295–7, 336–42, 368–71
Example write-up, 360–72
Important considerations in writing, 303–4
Introduction, 289–91, 311–16, 361–3
Length, 288
Method section, 291–3
Need for standardized format, 302
Overview, 287–8
Participants section, 292, 321–2, 364–5
Procedure section, 293, 323–4, 365–6
Reference section, 345–56
Results section, 293–5, 328–33, 366–8
Title, 289, 343–4
Writing style, 304–7
Research questions
Defining them, 33–6
Using books, 34
Using review articles, 35–6
See also Databases
Residual mean of squared errors, (MSR), see Mean of squared errors
Residual sum of squares (SSR), see Sum of squared errors
Sample, 110
Sample size, 111
See also Power
Sampling distribution, 132–4, 143
Sampling variability, 118, 120, 132
Scientific statements, 17–18
Self-report measures, see Measurement
Shapiro-Wilk test, 160
Simple effects analysis, 209
Single-subject experimental designs, 89–96,
Examples of, 93–5,
Rationale for, 92–3
Skew
Distribution, 114
And the Mean, 120
And the Median, 118
Positive skew, 114
Negative skew, 114, 161
Skin conductance, 44
Solomon four-group design, 78
Sphericity, 160, 183–8, 203, 213
Greenhouse-Geisser estimate, 186–8
Huynh-Feldt estimate, 186–8
Lower-bound estimate, 186, 188
Mauchly’s test, 160, 184, 185–6, 203, 213–14
Standard deviation, 128, 130
And distributions, 131
In populations and samples, 130
See also Deviation, Standard error, Sum of squared errors, Variance
Standard error, 134, 175–6
See also Sampling distribution, Standard deviation
Statistical tests
Selecting which to use, 265–9, 271–6
Statistics
Why we use them, 24–6
Sum of squared errors (SS) 126
Model sum of squares (SSM), 147–8, 173, 177, 180, 194–6, 205–7, 216–18, 225, 227
Residual sum of squares, (SSR), 147–8, 173, 177, 180, 194–6, 205–7, 216–18, 225, 227
Total sum of squares, (SST), 147–8, 173, 177, 180, 225
Systematic variance, 146
t-Test, 162–74
Assumptions, see Homogeneity of variance
Dependent (related) t-test, 168–72, 208, 224
General, 162–3
Independent t-test, 163–8, 224
And reporting results (dependent), 172
And reporting results (independent), 167–8
And SPSS (dependent), 168–70
And SPSS (independent), 166
See also Effect size
Tertium Quid, see Confounding variable
Test statistic, 146
Total sum of squares, SST, see Sum of squared errors
Tukey HSD, see Post hoc tests
Two-tailed test, 155
Two-way independent ANOVA, 191–201, 224
Assumptions, see Homogeneity of variance
And reporting results, 200–1
And SPSS, 192–7
When to use, 191
See also Effect size
Two-way mixed ANOVA, 201–12, 224
Assumptions, see Homogeneity of variance, Sphericity
And reporting results, 211–12
And SPSS, 202–9
When to use, 201
See also Effect size
Two-way repeated measures AN
OVA, 212–22, 224
Assumptions, see Sphericity
And reporting results, 221–2
And SPSS, 213–20
When to use, 212
See also Effect size
Type I error, 149–51, 172–3, 219, 247
Type II error, 151–2, 154, 184, 235
Unsystematic variance, 146
Validity, 44–7
Content validity, 44, 46
Criterion validity, 46–7
Ecological validity, 10
Factorial validity, 47
Maximizing, 58
Threats to internal validity, 58–62
Threats to external validity, 62–3
Variables
Continuous variable, 9–10
Definition, 5
Dependent variable, 21, 37, 42–51
Discrete variable, 9–10
Independent variable, 21, 37–40, 287
Levels of, 21, 40
Variance, 128
See also Sum of squared errors
Visual-analogue scales, 46
Wason selection task, 18–19
Web of science, see Databases
Wilcoxon signed-rank test, 239–43
And reporting results, 243
And SPSS, 240–2
When to use, 239
See also Effect size
Wilcoxon statistic for independent groups, 236
Writing style, 304–5
z-Score, 236