(Choose 1 answer)
According to a survey, the average student spends about 17 hours each week preparing for classes. Assume the standard deviation of time spent preparing for classes is 5 hours. If you select a random sample of 20 students, there is a 90% chance that the sample mean is less than how many hours per week?
Let P(z < -1.29) = 0.0985.; P(z < 1.29) = 0.9; P(z < -1.26) = 0.1038;
P(z < 1.26)= 0.8962.
A. 17
B. 19.54
C. 16.28
D. 18.44
E. None of the other choices is correct
Osh
Q: 29
