F (21, 1/2) and (a) k, (b) P(Y1 2 1 (4), and (c) P(Y: 2 1/2 12 = 1/4). 1. Suppose Y1, Y2, Ya, are independent gamma random variables each with parameters a = 4 and # = 3. Let W = Y1 + 2Y2 + 3Y3. (a) Find E[W]. Using Tchebysheff's Theorem find (b) a lower bound for P( W - E|W]