Here are the percentage returns on two stocks. a-1. Calculate the monthly variance and standard deviation d each stock. Note: Do not round intermediate calculations. Round your answers to 1 decimal places. a-2. Which stock is the riskier if held on its own? 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. Note: 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