Define a random variable Suppose A and B are two random variables, whose expected values are: E[A]=a, and E[B]=b. Evaluate E[_o A _1 B], where _o=2 and _1=-5. Suppose that the variables from question 2, A and B, are independent, and have variances V[A]=s_A, and E[B]=s_B. Evaluate V[_o A _1 B], where _o=2 and _1=-5. Let X=[1,2]', and let Y=[-7,12]'. Evaluate X'Y. What is a positive definite matrix