Which of the following best defines the Tukey post hoc test?

A researcher has 6 groups with 6 observations in each group. To look up the Tukey q critical value for alpha = 0.05, what degrees of freedom should they use from the ANOVA?

Two treatments A and B have means 7.2 and 5.1, equal sample sizes n = 9, and the ANOVA output reports MSE = 2.25. If the studentized range critical value qcrit = 3.60 for the chosen alpha and number of groups, compute q for A vs B and state the Tukey decision.

An agricultural trial compares three fertilizer formulas (X, Y, Z) with n = 8 plots per formula. The ANOVA rejects the overall null. The instructor provides qcrit = 3.40 for alpha = 0.05, k = 3 groups, and df = 21. Use MSE = 9.0 and group means X = 12, Y = 15, Z = 20. Compute all three pairwise q statistics and state which pairwise comparisons are significant at alpha = 0.05.

After an ANOVA rejects H0, you plan to run Tukey pairwise comparisons manually. Which sequence of steps correctly describes the procedure you should report in your methods section?