The mean and standard deviation of service times for customers
at a post office are known to be 2.93 minutes and 1.79 minutes,
respectively.
(a) Can you calculate the probability that the average service
time for the next two customers is less than 2.7 minutes? If so,
calculate the probability. If not, explain why not.
(b) What is the approximate probability that the total service
time for the next 65 customers exceeds three hours?
(Assume that the next 65 customers represent a simple random
sample and that there is always a customer
waiting in line.)