Question 1109598
Given all the assumptions, the interval is a t 0.975, df=25 *5/sqrt(26)
=1.71*5/sqrt(26)
or +/-1.68
(37.3, 40.7)

This is +/- z(0.975)*sqrt(.26*.74/350), or +/- 0.046
check is that for 95% CI the error is roughly 1/sqrt(n), so if n=400, error is 1/20 or 5%.