Here are the percentage returns on two stocks. Month Digital Cheese Executive Fruit January 15 % 7 % February 3 1 March 5 5 April 7 15 May 4 2 June 3 5 July 2 4 August 6 2 a-1. Calculate the monthly variance and standard deviation of each stock. (Do not round intermediate calculations. Round your answers to 1 decimal places.) a-2. Which stock is the riskier if held on its own? 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.) c. Is the variance more or less than half way between the variance of the two individual stocks? more than the 50%-50% less than the 50%-50%