The mean number of heart transplants performed per day in the United States in a recent year was about six. Find the probability that the number of heart transplants performed on any given day is
(a) Exactly seven,
(b) At least eight,
(c) No more than four.
Find the indicated probabilities using the geometric distribution, the Poisson distribution, or the binomial distribution. Then determine whether the events are unusual. If convenient, use a table or technology to find the probabilities.