The Decision Tree

Score
Dependency

Scale of
Measurement

Score
Distribution

Measure

SPSS Statistics Path

Independent
Scores

Interval or
Ratio

Symmetric
Homogeneous

t Test

Compare Means
- Independent Samples t test
-- Equal Variances Assumed

Symmetric
Nonhomogeneous

Welch's t Test

Compare Means
- Independent Samples t test
-- Equal Variances Not Assumed

Skewed in Different Directions

Mann-Whitney U
(Wilcoxon Rank Sum Test)

Nonparametric Tests
- 2 Independent Samples
-- Test Type: Mann-Whitney U

Ordinal

(not an issue)

Related
Scores

Interval or
Ratio

Symmetric
Difference Scores

Paired Samples
t Test

Compare Means
- Paired-Samples t test

Nonsymmetric
Difference Scores

Wilcoxon Test
for Paired Data

Nonparametric Tests
- 2 Related Samples
-- Test Type: Wilcoxon

Ordinal

(not an issue)