Nonparametric tests
Mann-Whitney U Test: When to Use It Instead of a T-Test (With Examples)
The nonparametric alternative to the independent t-test, explained with a worked example, effect size r and an APA-ready write-up.
Topic
Nonparametric tests
When and how to use Mann-Whitney U, Wilcoxon, Kruskal-Wallis and Friedman tests, with effect sizes and APA reporting examples.
Free Nonparametric tests tools
All 90+ tools →
Friedman Test CalculatorFree Friedman test calculator for three or more related measurements: chi-square, mean ranks, Kendall’s W and Bonferroni post-hoc Wilcoxon tests.Kruskal-Wallis H Test CalculatorFree Kruskal-Wallis H test calculator with mean ranks, tie correction, epsilon squared and Bonferroni-adjusted Dunn post-hoc tests.Mann-Whitney U Test CalculatorFree Mann-Whitney U test (Wilcoxon rank-sum) calculator with mean ranks, z, exact or asymptotic p-value and effect size r. For ordinal or skewed data.Wilcoxon Signed-Rank Test CalculatorFree Wilcoxon signed-rank test calculator for paired data: W, z, exact p-value for small samples and effect size r. The nonparametric paired t-test.