Question: Heather Carielli is a former student who earned a Master's degree at the University of Arkansas. When she randomly selected 16 new textbooks in the college bookstore, she found that they had prices with a mean of $70.41 and a standard deviation of $19.70. Is there sufficient evidence to warrant rejection of a claim in the college catalog that the mean price of a textbook at the college is less than $75.00? Use a 0.05 significance level.

For this problem, the critical value of the statistic is?