The manager of a computer retails store is concerned that his suppliers have been giving him laptop computers with lower-than-average quality. His research shows that replacement times for the model laptop of concern are normally distributed with a mean of 3.8 years and a standard deviation of 0.3 years. He decides to do a study and sample 32 laptops.
a. Find the probability that n = 32 randomly selected laptops will have a mean replacement time of 3.7 years or less.
b. Find the probability that n = 32 randomly selected laptops will have a mean replacement time between 3.82 and 3.87 years.