A Major Cell Phone Service Provider Has Determined That the Number

Multiple Choice

A major cell phone service provider has determined that the number of minutes that its customers use their phone per month is normally distributed with a mean equal to 445.5 minutes with a standard deviation equal to 177.8 minutes. The company is thinking of charging a lower rate for customers who use the phone less than a specified amount. If it wishes to give the rate reduction to no more than 12 percent of its customers, what should the cut-off be?

A) About 237 minutes
B) About 654 minutes
C) About 390 minutes
D) About 325 minutes