Suppose that a single-factor experiment with four levels of the factor has been conducted. There are six replicates and the experiment has been conducted in blocks. The error sum of squares is 500 and the block sum of squares is 250. If the experiment had been conducted as a completely randomized design the estimate of the error variance ????

2 would be.

(a) 25.0

(b) 25.5

(c) 35.0

(d) 37.5

(e) None of the above