Revisit Problem 6-55, but examine whether it would matter when you started monitoring the 911 calls if the time between occurrences had a uniform distribution with a mean of 2 and a range of 4.

a. Calculate the probability that no call comes in during the first hour.

b. Now suppose that you are monitoring the call frequency and you note that no call comes in during the first two hours. Determine the probability that no calls will arrive during the next hour.