Mann-Whitney U Test

Formula:

$$ \begin{aligned} U_1 & = n_1n_2 + \frac{n_1(n_1+1)}{2}-R_1\
U_2 & = n_1n_2 + \frac{n_2(n_2+1)}{2}-R_2\
\end{aligned} $$

The test statistic is $U=min{U_1,U_2 }$.

The critical value of U is $U_{\alpha, n1,n2}$

Suggestions and comments will be appreciated.