3. (:1) Give a reallife example, different from the examples and exercises in the textbook, in which the negative binomial distribution can be applied. (b) Let X ~ NBG', p}. Use the moment generating function for this distribution to show that: E[.X] = Ni). ((2) Explain why it does make sense that the expected value ofX - NEG", p} is directly proportional to 3" but inversely proportional to p