Solve the following questions manually, do not use excel. Show the formulas and solving clearly.

Here are the percentage returns on two stocks. a. Calculate the monthly variance and standard deviation of each stock. 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. c. Is the variance more or less than halfway between the variance of the two individual stocks