Question: Priority Mail is the U.S. Postal Service s alternative to commercial express mail companies such as FedEx. An article in The Wall Street Journal presented some interesting conclusions comparing Priority Mail shipments with the much less expensive first-class shipments (R. Brooks, New Data Reveal Priority Mail Is Slower Than a Stamp, The Wall Street Journal, May 29, 2002, p. D1). When comparing shipments intended for delivery in three days, firstclass deliveries failed to deliver on time 19% of the time, while Priority Mail failed 33% of the time. Note that at the time of the article, first-class deliveries started as low as $0.34, and Priority Mail started at $3.50. If 10 items are to be shipped first-class to 10 different destinations claimed to be in a three-day delivery location, what is the probability that
a. 0 items will take more than three days?
b. exactly 1 will take more than three days?
c. 2 or more will take more than three days?
d. What are the mean and the standard deviation of the probability distribution?