Name a nonparametric alternative to the independent samples t-test.

• A. Wilcoxon signed-rank test.
• B. Paired t-test.
• C. ANOVA.
• D. Mann-Whitney U test.

Answer: (D)

The main idea here is choosing a nonparametric method when comparing two independent groups. The Mann-Whitney U test fits that need because it doesn’t assume the data are normally distributed or that variances are equal. Instead of comparing means like the t-test, it ranks all observations from both groups together and examines whether one group tends to have higher ranks than the other. This makes it appropriate for ordinal data or continuous data that are skewed or don’t meet normality assumptions.

In this context, the Mann-Whitney U test is the best match for an independent-samples comparison without relying on parametric assumptions. It’s also known as the Wilcoxon rank-sum test. The other options either involve paired data (which calls for a Wilcoxon signed-rank test or a paired t-test) or are parametric methods for more than two groups (ANOVA) and thus don’t serve as the nonparametric alternative to the two-sample t-test.