Find the indicated probabilities using the geometric distribution, the Poisson distribution, or the binomial distribution. Then determine if the events are unusual. If convenient, use the appropriate probability table or technology to find the probabilities.

A newspaper finds that the mean number of typographical errors per page is six. Find the probability that

(a) exactly fourtypographical errors are found on a page,

(b) at most fourtypographical errors are found on a page,

(c) more than fourtypographical errors are found on a