how to solve these questions?

Do bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for Vanguard Total Stock Index (all stocks). Let y be a random variable representing annual return for Vanguard Balanced Index (60% stock and 40% bond). For the past several years, we have the following data. X: 19 0 25 33 34 16 38 18 14 11 y: 19 10 23 19 25 14 22 S 3 5 la use (a) Compute 2x, 2x2, 2y, Zyz. 2x 2x2 2y Eyz (b) Use the results of part (a) to compute the sample mean, variance, and standard deviation for x and for y. (Round your answers to four decimal places.) x y >