In a 4 x 4 factorial design with five subjects per cell, the df for the interaction F would be
A) 3, 70 df
B) 6, 64 df
C) 9, 64 df
D) none of the other alternatives are correct.

Question

Quizplus · Accepted Answer

In a 4 x 4 factorial design, the interaction term is calculated by multiplying the degrees of freedom for each factor (df for Factor A - 1) * (df for Factor B - 1). Each factor has 4 levels, so df for each is 3 (4-1). Thus, the interaction df = 3 * 3 = 9. With five subjects per cell and 16 cells (4x4), there are a total of 80 subjects. The total df = N - 1 = 80 - 1 = 79. Subtracting the df for the main effects and the interaction (3 + 3 + 9 = 15) from the total gives 79 - 15 = 64 for the error df.

In a 4 X 4 Factorial Design with Five Subjects