RESEARCH METHOD COHEN ok

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HOW MANY SAMPLES 587
give a frequently used example of an experiment
(Box 26.1).
In preceding chapters we have indicated which
tests are to be used with independent samples and
which are to be used with related samples.
Box 26.1
Identifying statistical tests for an experiment
With regard to the number of samples in the
test, there are statistical tests which are for single
samples (one group only, e.g. a single class in
school), for two samples (two groups, e.g. males and
females in a school) and for three or more samples
Chapter 26
Control group
→
t-test for independent
samples for the pretest
Wilcoxon test or t-test
for paired samples
(depending on data
type)
→
Control group
→
t-test for independent
samples for the post-test
Experimental
group
Wilcoxon test or t-test
for paired samples
(depending on data
type)
→
Experimental
group
Box 26.2
Statistical tests to be used with different numbers of groups of samples
Scale One sample Two samples More than two samples
of data
Independent Related Independent Related
Nominal Binomial Fisher exact test McNemar Chi-square (χ 2 )
k-samples test
Cochran Q
Ordinal
Interval
and ratio
Chi-square (χ 2 )
one-sample test
Kolmogorov-
Smirnov
one-sample test
Chi-square (χ 2 )
two-samples test
Mann-Whitney U test
Kolmogorov-Smirnov
test
Wald-Wolfowitz
Spearman rho
Ordinal regression
analysis
Wilcoxon
matched pairs test
Sign test
t-test t-test t-test for paired
samples
Kruskal-Wallis test
Ordinal regression
analysis
One-way ANOVA
Friedman test
Repeated
measures
ANOVA
Pearson product
moment correlation
Two-way ANOVA
Tukey hsd test
Scheffé test