Let x be a random variable assuming only nonnegative integer values, with probability
function
f_(x)(k)={(4 imes 5^(-k) for k=1,2,...),(0 otherwise ):}
(a) Find the probability generating function G_(x)(s).
(b) Verify that G_(x)(1)=1.
(c) Using the probability generating G_(x), derive E(x) and Var(x).
3. Let X be a random variable assuming only nonnegative integer values, with probability function 4 5-k for k=1,2,... fxk= 1 o otherwise (a) Find the probability generating function Gx(s).
(b) Verify that Gx(1) = 1.
(c) Using the probability generating Gx,derive E(X) and Var(X)