Sixty-eight percent of undergraduate students admit to cheating on tests or in written work. You randomly select six undergraduate students. Find the probability that the number of undergraduate students who admit to cheating on tests or in written work is 

(a) Exactly four, 

(b) More than two, and 

(c) At most five.

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.