Problem 7-12 Diversification Here are the percentage returns on two stocks. Month January February March April May June July August Digital Cheese 15% -4 5 7 -5 3 Executive Fruit 7% 2 5 13 1 5 -3 -1 a-1. Calculate the monthly variance and standard deviation of each stock. (Do not round intermediate calculations. Round your answers to 1 decimal places.) Digital Cheese Executive Fruit Variance Standard deviation % a-2. Which stock is the riskier if held on its own? O Digital Cheese O Executive Fruit b. Now calculate the variance and standard deviation of the returns on a portfolio that invests an equal amount each month in the two stocks. (Do not round intermediate calculations. Round your answers to 1 decimal places.) Variance Standard deviation %