The Wilcoxon Rank Sum Test (Like Most of the Non-Parametric

Short Answer

The Wilcoxon rank sum test (like most of the non-parametric tests presented in your textbook) actually tests to determine whether the population distributions have identical: $\begin{array}{|l|l|}\hline A&\text {locations. }\\\hline B&\text {spreads (variances). }\\\hline C&\text {shapes. }\\\hline D&\text { All of the above are correct answers.}\\\hline \end{array}$