Mann–Whitney U test
The Mann–Whitney U {\displaystyle U} test (also called the Mann–Whitney–Wilcoxon (MWW/MWU), Wilcoxon rank-sum test, or Wilcoxon–Mann–Whitney test) is a nonparametric statistical test of the null hypothesis that randomly selected values X and Y from two populations have the same distribution. The value of U calculated by the test can be converted to a measure of effect size by dividing it by the maximum value of U, which is the product of the sizes of the two samples being compared.