Here are the percentage returns on two stocks. Executive Fruit 9% Month January February March April May June July August Digital Cheese 15% -5 6 7 -6 4 -5 15 4 -5 -4 binen 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 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 %