Mann-Whitney U Test Calculator
Compare two independent samples with ranks, exact or asymptotic p-values, and effect sizes.
At a glance
- Computes
- Mann-Whitney U, an exact or asymptotic p-value, and rank-based effect sizes.
- You supply
- Two independent groups of values, an alternative, and a significance level.
- Use when
- Two independent groups, ordinal or skewed data, and you cannot assume normal means.
- Not for
- Paired or repeated measurements on the same subjects.
Mann-Whitney U
Enter samples
Auto chooses exact when ties allow.
| Metric | Value |
|---|
| Value | Group | Rank |
|---|
Density by Mann-Whitney U; 5 bins of width 1 (fd rule); P-value tail; Observed U 0
U1 = R1 - n1(n1 + 1) / 2
How?
How this is calculated
The calculator ranks all observations together, assigns average ranks to ties, and computes U for group 1. Exact mode uses the no-tie U distribution. Asymptotic mode uses the normal approximation with tie correction and a continuity correction.
Formula: U1 = R1 - n1(n1 + 1) / 2
Sources
- SciPy mannwhitneyu. SciPy. Retrieved .
- Mann and Whitney 1947 paper. Project Euclid. Retrieved .
Method last reviewed