What is the name of the test statistic that follows the F-distribution and compares explained to unexplained variability to assess model fit and differences between group means?

• A. F-statistic
• B. Eta squared (η2)
• C. Exp(B)
• D. Cross-sectional

Answer: (A)

In ANOVA, the F-statistic is the test statistic that follows the F-distribution and compares explained variance to unexplained variance to assess model fit and differences between group means. It’s calculated as the ratio of the mean square between groups to the mean square within groups, so a larger value suggests that the between-group differences are substantial relative to random error. This helps determine whether not all group means are equal.

Eta squared is an effect size measure, not a test statistic. Exp(B) appears in interpreting logistic regression coefficients. Cross-sectional refers to a study design, not a statistic.