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.