Rank sum test
A test of the homogeneity of two samples $X_1,\dots, X_n$ and $Y_1,\dots, Y_m$ based on the rank statistic $R_1+\dots +R_m$ — the sum of the ranks $R_j$ of the random variables $Y_j$ in the joint series of order statistics (cf. Order statistic) of $X_i$ and $X_j$ (the elements of the two samples are mutually independent and come from continuous distributions). It is a variant of the Wilcoxon test.
Rank sum test. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Rank_sum_test&oldid=31011