Let XXX follow the Geometric distribution P(X=k)=(1−p)k−1pP(X=k) = (1-p)^{k-1}pP(X=k)=(1−p)k−1p. What is E[X]E[X]E[X]?
1/p1/p1/p
1−p1-p1−p
ppp
(1−p)/p2(1-p)/p^2(1−p)/p2