In this framework, what is the term for the overall test of whether group means differ after covariate adjustment?

In this framework, what is the term for the overall test of whether group means differ after covariate adjustment?

• A. ANOVA
• B. MANOVA
• C. Analysis of covariance
• D. Multiple regression

Answer: (C)

When you want to compare group means after removing the influence of one or more covariates, the approach used is Analysis of Covariance. It blends ANOVA and regression by including the covariate(s) as predictors along with the group membership. The key test is the F-test for the group factor, which asks whether the adjusted means differ after accounting for the covariate. If this test is significant, it means the groups have different means even after you control for the covariate, rather than differences being due to the covariate itself. The covariate helps explain some of the variance, leaving a cleaner comparison of the group means. The other options don’t fit as well because: ANOVA compares group means without adjusting for covariates; MANOVA handles multiple dependent variables simultaneously; multiple regression analyzes the relationship between a dependent variable and predictors (which can include group indicators), but it doesn’t provide the standard, direct test of adjusted group means across groups in the same, widely used framework as ANCOVA.

When you want to compare group means after removing the influence of one or more covariates, the approach used is Analysis of Covariance. It blends ANOVA and regression by including the covariate(s) as predictors along with the group membership. The key test is the F-test for the group factor, which asks whether the adjusted means differ after accounting for the covariate. If this test is significant, it means the groups have different means even after you control for the covariate, rather than differences being due to the covariate itself. The covariate helps explain some of the variance, leaving a cleaner comparison of the group means.

The other options don’t fit as well because: ANOVA compares group means without adjusting for covariates; MANOVA handles multiple dependent variables simultaneously; multiple regression analyzes the relationship between a dependent variable and predictors (which can include group indicators), but it doesn’t provide the standard, direct test of adjusted group means across groups in the same, widely used framework as ANCOVA.