Question: The amount of time a bank teller spends with each customer has a population mean µ=3.10 minutes and standard deviation σ=0.40 minute. If you select a random sample of 16 customers:

A) What is the probability that the mean time spent per customer is less than 3 minutes?

B) There is an 85% chance that the sample mean is below how many minutes?

C) If you select a random sample of 64 customers, there is a 85% chance that the sample mean is below how many minutes?

The book gives these two answers to a and b: a-0.8413 and b-3.204