The Mean and the Standard Deviation of W for the Nonparametric

Multiple Choice

The mean and the standard deviation of W for the nonparametric Wilcoxon rank sum test:

A) depend entirely upon the characteristics of the two samples.
B) depend entirely upon the characteristics of the two populations.
C) depend on the number of items that are being ranked, but not on the values themselves.
D) depend on the number of items that are being ranked, as well as the values themselves.