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

A newspaper finds that the man number of typographical errors per page is three. Find the probability that (a) exactly four typographical errors are found on a page , (b), at most four typographical errors are found on a page, and (c) more than four typographical errors are found on a page.

Which events are unusual?