An ANOVA is used to evaluate the mean differences for a rese

An ANOVA is used to evaluate the mean differences for a research study comparing four treatments with a separate sample of n = 5 in each treatment. If the data produce an F ratio of 3.15, then which of the following is the correct statistical decision?

A. Reject the null with = .05, but not with = .01

B. Reject the null with either = .05 or = .01

C. Fail to reject the null with either = .05 or = .01

D. There is not enough information to make a statistical decision

Solution

Here,

df1 = number of groups - 1 = 4 -1 = 3
df2 = number of participants - number of groups = 4*5 - 4 = 16

Thus, the critical F at 0.05 and 0.01 is

Fcrit(0.05) = 3.238871517
Fcrit(0.01) = 5.292214046

Thus, since at both levels, Fcrit > F, then

OPTION C: Fail to reject the null with either = .05 or = .01 [ANSWER]