Telephone Survey: A telephone survey uses a random digit dialing machine to call subjects. The random digit dialing machine is expected to reach a live person 15% of the time. In eight attempts, what is the probability of achieving exactly two successful calls?

You should produce the PMF and the histogram for this Binomial distribution before you answer the question.

This is a continuation of the problem begun in 6.5. Be sure to answer questions (a) and (b).
A random digit dialing machine with p =0.15 for each call attempt.
(a) What is the expected value and variance for the number of contacts in eight attempts?
(b) What is the expected value and variance for 50 attempts?