Calculate monthly returns for ExxonMobil and Walmart for this period. Q.2). Calculate the average return, variance, and standard deviation of returns for each firm. (Use Excel's AVERAGE, VAR and STDEV functions.) Q.3). Which stock is riskier if held on its own? Why? Q.4). Assume that you held an equally weighted portfolio of ExxonMobil andWalmart (i.e., a portfolio with equal dollar investments in each stock). Compute the portfolio's rate of return for each month, and calculate the variance and standard deviation of the portfolio's monthly rate of return. Q.5). Is the portfolio standard deviation more or less than the average of thestandard deviations of the two component stock? Q.6). What are the betas provided by finance.yahoo.com for each firm? Which-stock has more systematic risk?