Perform a Mann-Whitney U test comparing two independent samples.
The Mann-Whitney U test compares distributions without assuming normality, using only the ordering of observations. The effect size r converts the z statistic into a scale-free magnitude. It tests whether one distribution is stochastically larger than the other, which is a broader claim than a difference in means.
Mann Whitney U
E(U) = n₁n₂/2; SD(U) = √(n₁n₂(n₁+n₂+1)/12); z = (U − E(U)) ÷ SD(U)
E(U) = n₁n₂/2; SD(U) = √(n₁n₂(n₁+n₂+1)/12); z = (U − E(U)) ÷ SD(U) The Mann-Whitney U test compares distributions without assuming normality, using only the ordering of observations. The effect size r converts the z statistic into a scale-free magnitude.
It tests whether one distribution is stochastically larger than the other, which is a broader claim than a difference in means.
This calculator takes 4 inputs: U statistic, Sample size of group 1, Sample size of group 2, Significance level. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.