4. Let X be a discrete random variable with the following distribution: P(X = -3) =a, P(X =-2) = 32, P(X = -1) = b, P(X = 0) = 5 16: P(X = 1) = C, P(X = 2) = 32 a. Find a, b, c. b. Calculate E(3+ 2X ), E(3+2X)', Var(3 + 2X). 5. Derive the expected value of the random variable X with distribution Negative Binomial(r, p)