25. Given below is a bivariate distribution for the random variables x and y. f(x, y) 50 30 40 80 50 60 a. Compute the expected value and the variance for x and y. b. Develop a probability distribution for x + y. c. Using the result of part (b), compute E(x + y) and Var (x + y). d. Compute the covariance and correlation for x and y. Are x and y positively related, negatively related, or unrelated? e. Is the variance of the sum of x and y bigger, smaller, or the same as the sum of the individual variances? Why