Answer:
Her friend Eric, however, thinks she would have scored just as well without the class, is proved at 5% significance level
Explanation:
Given that sample size is 17 and distribution is normal
Since sima, population std dev is not known, we can use only t test.
Set hypotheses as

(Right tailed test)

Mean difference =

Std error of sample mean = s/square root of n
=

Test statistic t = mean diff/std error
= 0.3443
df = 16
p value = 0.369
Since p >0.05, at 5% significant level we conclude that there is no significant difference because of attending preparatin class.