Probability using Normal distribution.

A study group of long distance phone calls made from the corporate offices of Pepsi Bottling Group, Inc., in Somers, New York, revealed length of the calls, in minutes, follows normal probability distribution. The mean length of time per call was 4.2 minutes and the standard deviation was 0.60 minutes.

a. What fraction of calls last between 4.2 and 5 minutes?

b. What fraction of calls last more than 5 minutes?

c. What fraction of calls last between 5 and 6 minutes?

d. What fraction of calls last between 4 and 6 minutes?

e. As part of her report to the president, director of communications would like to report length of the longest (in duration) 4 percent of calls. What is this time?