The scheduled arrival time for a daily l ight from Boston to New York is 9: 25 am. Historical data show that the arrival time follows the continuous uniform distribution with an early arrival time of 9: 15 am and a late arrival time of 9: 55 am.
a. Calculate the mean and the standard deviation of the distribution.
b. What is the probability that a light arrives late (later than 9: 25 am)?