1. A sales rep for national clothing company makes four calls per day. Based upon historical records, the following probability distribution states the number of successful calls each day:
The expected number of successful sales calls for each day is:
2. A package delivery service claims that no more than five percent of all packages arrive at address late. Supposing that the conditions for binomial hold, if the sample of size 10 packages is randomly chosen, and the five percent rate holds, find out the probability that exactly 2 packages in sample arrive late?