On a dry surface, the braking distance (in meters) of a Cadillac is normally distributed with a mean of 48m and standard deviation 2.1m.
A. What is the probability that a randomly selected Cadillac has a braking distance between 50m and 54m?
B. What braking distance of a Cadillac represents the first quartile?
C. The 11% of Cadillac's with the longest braking distance have a braking distance of at least what distance?
Replacement times for DVD players are normally distributed with a mean of 8.9 years and standard deviation of 1.8 years. If you want to provide a warranty so that only 4% of the DVD players will be replaced before the warranty expires, what is the time length of the warranty in years?