The table below shows historical annual returns for stocks of companies X and Y over recent years. Calculate the arithmetic average returns. In addition, calculate their historical variances, as well as their historical standard deviations. Requirement 1: (a) The arithmetic average return of company X 's stock is (b) The arithmetic average return of company Y's stock is: Requirement 2: (a) The historical variance of company X 's stock returns is (Do not round intermediate a) calculations.) (b) The historical variance of company Y's stock returns is (Do not round intermediate) calculations.) Requirement 3: (a) The historical standard deviation of company X 's stock returns is (Do not round (a) intermediate calculations.) (b) The historical standard deviation of company Y's stock returns is (Do not round intermediate colculations.)