Question

Assume the standard deviation of time spent preparing for classes is 4 hours. If you select a random sample of 16 students,

a. what is the probability that the mean time spent preparing for classes is at least 14 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 students, there is an 85% chance that the sample mean is less than how many hours per week?

Answer 1

a. what is the probability that the mean time spent preparing for classes is at least 14 hours per week?

x = 14

z = -0.25

p-value = 0.4013

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

22.76 hours

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

I must make the assumption that the population is normally distributed

d. if you select a random sample of 64 students, there is an 85% chance that the sample mean is less than how many hours per week?

21.15 hours