Which of the following is NOT considered a post hoc test for independent groups?

The reason why Friedman's test is the correct choice as not being a post hoc test for independent groups lies in its specific application in statistical analysis. Friedman's test is actually a non-parametric test used to detect differences in treatments across multiple test attempts. It is appropriate for related samples, which means it is used when the same subjects are tested multiple times or under different conditions, thereby assessing related rather than independent groups.

In contrast, the Bonferroni test, Sidak test, and Dunnett test are all designed for use following an ANOVA with independent groups to determine which specific group means are significantly different from one another after an overall significant result has been found. The Bonferroni and Sidak tests specifically adjust for multiple comparisons, while Dunnett’s test is used when comparing multiple groups against a single control group.