An ANOVA procedure is used for data that were obtained from four sample groups each comprised of five observations. The degrees of freedom for the critical value of F are .

(3,16)

Step-by-step explanation:

The degrees of freedom of the critical value F are (k-1,n-k).

We are given that there are four sample group, so,

k=4.

Also, we are given that the each four groups contains five observations, so,

n=4*5

n=20

The critical value F has degree of freedom

(k-1,n-k)

(4-1,20-4)

(3,16).

Thus, the degrees of freedom for the critical value of F are (3,16).

answer: x=60