Standard normal distribution probability

[trastic]

"A study of long distance phone calls made from the corporate offices of the Pepsi Bottling Group Inc. showed the calls follow the normal distribution. The mean length of time per call was 4.2 minutes and the standard deviation was 0.60 minutes.
a.What is the probability the calls lasted between 4.2 and 5 minutes?
b. What is the probability the calls lasted more than 5 minutes?
c. What is the probability the calls lasted between 5 and 6 minutes? d. What is the probability the calls lasted between 4 and 6 minutes?
e. As part of her report to the president,the director of communications would like to report the minimum
length of the longest (in duration) 4 percent of the calls. What is this time?"

 

[Prove It]

"A study of long distance phone calls made from the corporate offices of the Pepsi Bottling Group Inc. showed the calls follow the normal distribution. The mean length of time per call was 4.2 minutes and the standard deviation was 0.60 minutes.
a.What is the probability the calls lasted between 4.2 and 5 minutes?
b. What is the probability the calls lasted more than 5 minutes?
c. What is the probability the calls lasted between 5 and 6 minutes? d. What is the probability the calls lasted between 4 and 6 minutes?
e. As part of her report to the president,the director of communications would like to report the minimum
length of the longest (in duration) 4 percent of the calls. What is this time?"

Well for starters, since you have been TOLD to use the standard normal distribution, what are the standard (z) values that correspond to values in this distribution of 4.2, 5 and 6?