Chapter 7, Problem 8PS

Today, full-time college students report spending a mean of 27 hours per week on academic activities, both inside and outside the classroom. Assume the standard deviation of time spent on academic activities is 4 hours. If you select a random sample of 16 full-time college students.

a. what is the probability that the mean time spent on academic activities is at least 26 hours per week?

b. there is an $85\%$ chance that the sample mean is less than how many hours per week?

c. What assumption must you make in order to solve (a) and (b)?

d. If you select a random sample of 64 full-time college students. there is an $85\%$ chance that the sample mean is less than how many hours per week?