If the underlying distributions are known to be symmetric, we can use the Wilcoxon rank-sum test to compare two independent population means.This is so because:
A) the rank-sum test is designed as a test of two independent means.
B) the mean and the median have the same value for all symmetric distributions.
C) the mean is the parameter that is usually evaluated when using nonparametric procedures.
D) the difference in two population means will always be normally distributed and the Wilcoxon rank-sum test is used to test normally distributed variables.

Question

Quizplus · Accepted Answer

When the underlying distributions are known to be symmetric, the mean and the median have the same value for all symmetric distributions. Therefore, we can use the Wilcoxon rank-sum test to compare two independent population means, as it is designed to compare the medians of two samples.

If the Underlying Distributions Are Known to Be Symmetric, We