Which statistical test is typically used to compare the means of two independent groups?

• A. Independent samples t-test
• B. Paired t-test
• C. One-way ANOVA
• D. Chi-square test

Answer: (A)

When you want to know if two independent groups differ in their average outcome, you typically use an independent samples t-test. This test evaluates whether the observed difference between the two group means is larger than what we’d expect from random sampling, taking into account the variability within each group and the sample sizes. It relies on the data being roughly normally distributed within each group and assumes similar variances; if the variances aren’t equal, a version with a Welch correction can be used.

The paired t-test would be used when the two samples are related or matched, not independent groups. One-way ANOVA is for comparing means across three or more groups; with exactly two independent groups, the t-test and ANOVA yield equivalent conclusions, but the t-test is the direct choice. The chi-square test is for categorical data, not for comparing means. If normality or equal-variance assumptions are violated, a nonparametric alternative like the Mann-Whitney U test can be appropriate.