Lets modify Exercise 15.12 to have sample means of 25 and 28, with a pooled standard deviation

Question:

Let’s modify Exercise 15.12 to have sample means of 25 and 28, with a pooled standard deviation of 8 and sample sizes of 20 and 20.
(a) What is the a priori power of this experiment?
(b) Run the t test on the data.
(c) What, if anything, does the answer to (a) have to say about the answer to (b)?