4. Let X~Gamma(a, ,8). a. Prove thatE [X] = (1,8. b. Prove that Var[X] = 05,82 (1 c. Prove that MX(t) = (12%) d. What is the meaning of ,8 and what is the meaning of dB? Dene each quantity (3 and (1,8) in terms of average waiting times until { [ill in the blank }