Here are the returns on two stocks. Digital Cheese Executive Fruit January +16 +9 February 4 +1 March +6 +7 April +8 +16 May 5 +2 June +4 +7 July 3 4 August 9 3 Required: a-1. Calculate the variance and standard deviation of each stock. a-2. Which stock is riskier if held on its own? b. Now calculate the returns in each month of a portfolio that invests an equal amount each month in the two stocks. c. Is the variance more or less than halfway between the variance of the two individual stocks?