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 calculations.) (b) The historical variance of company Y 's stock returns is: (Do not round intermediate Requirement 3: (a) The historical standard deviation of company X's stock returns is: (Do not round (a) Intermediate calculations.) The historical standard deviation of company Y's stock returns is: (Do not round (b) intermediate calculations.)