Suppose that X is a random variable with mean /x and standard deviation ox. What is the mean (expected value) of Z = X-px 7 JX Select one: a. Depends on the values of #x, Ox b. E(Z) = 1 c. E(Z) = 0 d. E(X)Let X, Y be random variables. Find the variance var(X + Y), where var(X) = 2, var()) = 2, and the correlation is corr(X, Y) = -0.4. Answer:Let X, Y be two random variables and a, bare scalars. Then E(aX + by) = Select one: a. abE(X)E(Y) b. (a+ b) (E(X) + E(Y) ) c. a+b+ E(X) + E(Y) d. aE(X) + bE(Y)Let X, Y be random variables and a, b scalars (numbers). Find the expected value E(a . X + b . Y), where ux = 3, My = 10, a = 5, b = 5. Answer:Let X, Y be two independent random variables. Then it follows that var(X + Y) = var(X) + var(Y). Select one: True False