Suppose that X1, X2, . . . are iid random variables taking values in {0, 1, . . .}. Let pk = P(X1 = k) for k = 0, 1, . . .. Let N be the smallest integer n such that X1 + + Xn 20. (a) What is E(X1 + + XN )? Your answer will use a theorem and not give you a number - just an alternative formula for the expected value. (b) If pk = 0 for all k 2 what is X1 + + XN . (c) Use the previous two parts to compute E(N).