Eighteen percent of U.S. adults say they use Reddit. You randomly select seven U.S. adults. Find the probability that the number who use Reddit is

(a) exactly one,

(b) more than three, and

(c) from two to four.

In Exercises 11–26, 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.