Question 3. Suppose that the random variable X is defined as X 0.6X1 +0.3X2 +0.1X3, where the probability distributions of the independent random variables X1, X2, and X3 are Ix, (=) = (:)0.1-0,9-, fx. (a) = (")0.r0.0-. %3D fx2 (x) = %3D and fx, (2) = (")0.60.4*-*, %3D x = 0, 1,...,5. a) Evaluate the mean of X. b) Evaluate the variance of X.