17. A one-way ANOVA is carried out using the performance scores from 17. five different treatment groups of nine cases each. A significant F is obtained. For this analysis s2 within 20 5, and the treatment group means are as follows:

X1 20 3 X2 12 2 X3 15 3 X4 13 6 and X5 19 1

(a) Use the formula k(k− 1) 2 to determine the number of all possible pairs of means.

(b) Display the differences between the means for all possible pairs of samples as illustrated in Section 16.8 (step 3).

(c) Apply the Tukey test (α 05) to all possible pairwise comparisons between means and draw final conclusions.

(d) Repeat Problem 17c using α 01.