Calculate the standard deviation of monthly returns for the two stocks and the S&P $500$ using

Excel. What is the annualized standard deviation for the two stocks and the S&P $500($Hint:

convert the monthly standard deviation into annual standard deviation by multiplying the

square root of $12,$ i$.$e$.,3\mathrm{.}4641.)?$ Among the two stocks and the S&P $500,$ which one has the

lowest total risk? What is the $95\%$ confidence interval of future returns for these two stocks

using the annualized average return and annualized standard deviation?