Question 12 Do bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for the Vanguard Total Stock Index (all Stocks). Let y be a random variable representing annual return for the Vanguard Balanced Index (60% stock and 40% bond). For the past several years, assume the following data. Compute El. 12 0 39 23 31 25 26 -12 -12 ~23 9 3 26 15 24 17 15 -3 -4 9 133 109 155 78 132