# statistics

posted by
**kevin**
.

The duration of time it takes General Motors to build a car is normally distributed with a mean of 31 hours and a standard deviation of 2 hours.

a) What is the probability that a single car, selected at random,

will take between 28 and 34 hours?

b) What is the probability that the mean of the times for a sample

of 25 cars will be between 28 and 34 hours?