Please help me with answer (d)

K The probability model below describes the number of repair calls that an appliance repair shop may receive during an hour. Repair Calls 0 2 3 Probability 0.2 03 0.3 0.2 On average, the shop receives 1.5 calls an hour, with a standard deviation of 1 02 calls. Suppose that the appliance shop plans an 8-hour day. Complete parts (a) through (d) below O A. The shop is open on weekends. O B. Each call lasts less than 1 hour O C. The hours are independent O D. The shop receives the same number of calls each day. (c) Use the mean and standard deviation to describe what a typical 8-hour day will be like. Assume that a variation of 1 standard deviation is typical. A typical 8-hour day will have about 2.43 to 20.97 repair calls (Round to the nearest integer as needed. Use ascending order ) (d) At the end of a day, a worker comments "Boy, I'm tired. Today was sure unusually busy!" How many repair calls would justify such an observation? Assume that a variation of 2 standard deviations is unusual. The smallest observation that would be considered unusual is | |repair calls. (Round up to the nearest integer.)