A study of long-distance phone calls made from General Electric's corporate headquarters in Fairfield, Connecticut, revealed length of the calls, in minutes, follows normal probability distribution. The mean length of time per call was 4.6 minutes and the standard deviation was 0.50 minutes.
(a) What fraction of the calls last between 4.6 and 5.4 minutes?
(b) What fraction of the calls last more than 5.4 minutes?
(c) What fraction of the calls last between 5.4 and 6 minutes?
(d) What fraction of the calls last between 4 and 6 minutes?
(e) As part of her report to the president, the director of communications would like to report the length of the longest (in duration) 6% of the calls. What is this time?