The Local Swim Team Is Considering Offering a New Semi-Private $\sigma$

Multiple Choice

.The local swim team is considering offering a new semi-private class aimed at entry-level swimmers,but needs a minimum number of swimmers to sign up in order to be cost effective.Last year's data showed that during 8 swim sessions the average number of entry-level swimmers attending was 15.Suppose the instructor wants to conduct a hypothesis test and the alternative hypothesis is "the population mean is greater than 15"If the sample size is 5 $\sigma$ is known,and alpha = .01,the critical value of z is _______.

A) 2.575
B) -2.575
C) 2.33
D) -2.33
E) 2.45