A statistical analysis of 1,000 long-distance calls made from the headquarters of the Bricks and Clicks Computer Corporation indicates that the length of these calls is normally distributed with μ = 240 seconds and σ = 40 seconds.
a. What is the probably that a call lasted less than 180 seconds?
b. What is the probability that a particular call lasted between 180 and 300 seconds?
c. What is the probability that a call lasted between 110 and 180 seconds?
d. What is the length of a call if only 1% of all calls are shorter?