6. In a pilot study examining the effectiveness of three commercials (A, B, and C), 10 consumers were assigned to view each commercial and rate it on a 9-point Likert scale. The data obtained are shown in the following table. These data should be analyzed by doing hand calculations (i.e., without using the computer).

Commercial A B C 4 7 8 5 4 7 3 6 7 4 5 6 3 4 8 4 6 7 4 5 8 3 5 8 5 4 5 5 4 6

a. Calculate the category means and the grand mean.

b. Calculate SSy, SSx, and SSerror.

c. Calculate η2.

d. Calculate the value of F.

e. Are the three commercials equally effective?