MWW - Mann-Whitney-Wilcoxon distribution
The Mann-Whitney-Wilcoxon distribution is a discrete distribution. It describes the distribution of uStat.
A set of observations of variable x is split into two sets. It is assumed that the values of the variable x are independent and equally distributed in both sets. It is also assumed that x is ordinal so that all values of x can be ranked.
The uStat statistics value is calculated as the sum of ranks of objects that belong to the set that contains the fewest items.
The Mann-Whitney-Wilcoxon distribution has two parameters, the number of items in the first set, and the total number of items.