7 In the grafting context of Exercise 1 suppose that grafts

7. In the grafting context of Exercise 1, suppose that grafts are done one at a time and the process continues until the first failed graft. Let X denote the number of grafts up to and including the first failed graft. (a) The random variable X is (choose one (b) binomial (ii) hypergeometric (iii) negative binomial (iv) Poisson. (b) Give the sample space and PMF of X. (c) Give the expected value and variance of X.

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