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?

2 answers

in

http://davidmlane.com/normal.html

I entered:
mean -- 48.2
SD ---- 13.4
click on "above" and enter 60 (for 1 hour) to get
.1893

etc
78