Between-group variability in ANOVA refers to which of the following?

Between-group variability in ANOVA refers to which of the following?

• A. The difference WITHIN the scores of the groups.
• B. The difference BETWEEN the mean scores for the groups.
• C. The total variance across all observations.
• D. The average variance within each group.

Answer: (B)

In ANOVA, total variability is split into two parts: variability between the groups and variability within the groups. Between-group variability measures how far the group means are from the overall grand mean—essentially, how much the average score differs from one group to another. This is captured by the differences between the mean scores for the groups. If those means spread out a lot compared with how much individual scores vary within each group, the between-group part is large, which is what the F-statistic compares to the within-group variability. The other options describe variability inside groups (within-group), the entire set of observations (total variance), or the average of within-group variances, none of which reflect differences among group means.

In ANOVA, total variability is split into two parts: variability between the groups and variability within the groups. Between-group variability measures how far the group means are from the overall grand mean—essentially, how much the average score differs from one group to another. This is captured by the differences between the mean scores for the groups. If those means spread out a lot compared with how much individual scores vary within each group, the between-group part is large, which is what the F-statistic compares to the within-group variability. The other options describe variability inside groups (within-group), the entire set of observations (total variance), or the average of within-group variances, none of which reflect differences among group means.