Question

When an opinion poll calls residential telephone numbers
at random, only 20% of the calls reach a live person. You watch the random digit
dialing machine make 15 calls.

(a) What is the probability that exactly 5 calls reach a person?

Answer 1

Use binomial distribution\[P(k)=\left(\begin{matrix}n \\ k\end{matrix}\right)p^k(1-p)^{n-k}\] where n=15, k=5 and p=0.2

Answer 2

.1032 use the binomial distribution table