# Question

An English literature course was taken by 250 students. Each member of a random sample of 50 of these students was asked to estimate the amount of time he or she spent on the previous week's assignment. Suppose that the population standard deviation is 30 minutes.
a. What is the probability that the sample mean exceeds the population mean by more than 2.5 minutes?
b. What is the probability that the sample mean is more than 5 minutes below the population mean?
c. What is the probability that the sample mean differs from the population mean by more than 10 minutes?

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