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

• A. T test
• B. F test
• C. Chi-Square test
• D. ANOVA

Answer: (A)

To determine whether two groups differ in their average value of a continuous outcome, you use a t test. This test checks whether the observed difference between the group means is larger than what would be expected by random sampling error, given how much individuals vary within each group. It does this by standardizing the difference with the variability and sample sizes, producing a t statistic and a p-value that tell you if the difference is statistically significant. Use a two-sample t test when the groups are independent and the outcome is measured on a scale that supports computing means, with assumptions about normality and reasonably similar variances (or apply Welch’s version if variances may differ). If the data are paired or matched, a paired t test is appropriate, as it accounts for the within-pair differences. The F test is used to compare variances (and underpins ANOVA), not directly to compare means of two groups. The Chi-Square test is designed for categorical data. And ANOVA is used to compare means across three or more groups (though with exactly two groups, it yields results equivalent to the t test).