In the Wilcoxon Rank-Sum Test, the Null Hypothesis May Be

Multiple Choice

In the Wilcoxon rank-sum test, the null hypothesis may be expressed as: ​ ​
If , then:

A) the test is not valid.
B) we can conclude that the null hypothesis is true and there is no difference in the two population medians only if the sample provides sufficient support for this assertion.
C) there is insufficient evidence to reject the null hypothesis, but nothing is said about the validity of the null hypothesis.
D) the median of population 1 is equal to the mean of population 2, provided both populations are heavily skewed.