Supplier on-time delivery performance is critical to enabling the buyer’s organization to meet its customer service commitments. Therefore, monitoring supplier delivery times is critical. Based on a great deal of historical data, a manufacturer of personal computers ﬁnds for one of its just-in-time suppliers that the delivery times are random and well approximated by the Normal distribution with mean 48.2 minutes and standard deviation 13.4 minutes.
(a) What is the probability that a particular delivery will exceed one hour?
(b) Based on part (a), what is the probability that a particular delivery arrives in less than one hour?
(c) What is the probability that the mean time of 5 deliveries will exceed one hour?