A posthoc test is warranted when A we fail to reject the nul

A post-hoc test is warranted when:

A) we fail to reject the null hypothesis in an ANOVA.

B) the F is significant and there are more than two groups.

C) we reject the null hypothesis when performing an independent-groups t test.

D) we have an a priori prediction about which group means will differ.

Solution

A post-hoc test is warranted when:

B) the F is significant and there are more than two groups. Post hoc tests are usually run only to confirm that the differences occurred between groups and they should be computed only when there is an overall significant difference in group means.