Suppose the annual demand for Soni DVD players at an appliance store is normally distributed with mean 150 and standard deviation 45. When the store orders these DVD players from its supplier, it...

Suppose the annual demand for Soni DVD players at an appliance store is normally distributed with mean 150 and standard deviation 45. When the store orders these DVD players from its supplier, it takes an amount of time L for the order to arrive, where L is measured as a fraction of a year. In each of the following, find the mean
LD and the standard deviation
LD of the demand during lead time.

a. Assume that L is known to be 3/52, that is, three weeks.

b. Assume that L is uncertain, with mean 3/52 and standard deviation 1/52.