Please help me with PART B of question below. I need help with the formula

EVALUATING RISK AND RETURN Bartman Industries's and Reynolds Inc.'s stock prices and dividends, along with the Winslow 5000 Index, are shown here for the period new company purchasing the stock? COMPREHENSIVE/SPREADSHEET PROBLEM 8-22 Winslow 5000 2009-2014. The Winslow 5000 data are adjusted to include dividends. Bartman Industries Reynolds Inc. Dividend Includes Dividends Year Stock Price Dividend Stock Price $3.00 2014 $17.25 14.75 $48.75 52.30 2.90 $1.15 1.06 1.00 2013 48.75 2.75 2012 16.50 10.75 $11,663.98 8,785.70 8,679.98 6,434.03 5,602.28 4,705.97 57.25 2011 2.50 2.25 2010 11.37 0.95 0.90 0.85 60.00 2009 7.62 55.75 2.00 a. Use the data to calculate annual rates of return for Bartman, Reynolds, and the Winslow 5000 Index. Then calculate each entity's average return over the 5-year period. (Hint: Remember, returns are calculated by subtracting the beginning price from the ending price to get the capital gain or loss, adding the dividend to the capital gain or loss, and dividing the result by the beginning price. Assume that dividends are already included in the index. Also, you cannot calculate the rate of return for 2009 because you do not have 2008 data.) Calculate the standard deviations of the returns for Bartman, Reynolds, and the Winslow 5000. (Hint: Use the sample standard deviation formula, Equation 8.2a in this chapter, which corresponds to the STDEV function in Excel.) b. EVALUATING RISK AND RETURN Bartman Industries's and Reynolds Inc.'s stock prices and dividends, along with the Winslow 5000 Index, are shown here for the period new company purchasing the stock? COMPREHENSIVE/SPREADSHEET PROBLEM 8-22 Winslow 5000 2009-2014. The Winslow 5000 data are adjusted to include dividends. Bartman Industries Reynolds Inc. Dividend Includes Dividends Year Stock Price Dividend Stock Price $3.00 2014 $17.25 14.75 $48.75 52.30 2.90 $1.15 1.06 1.00 2013 48.75 2.75 2012 16.50 10.75 $11,663.98 8,785.70 8,679.98 6,434.03 5,602.28 4,705.97 57.25 2011 2.50 2.25 2010 11.37 0.95 0.90 0.85 60.00 2009 7.62 55.75 2.00 a. Use the data to calculate annual rates of return for Bartman, Reynolds, and the Winslow 5000 Index. Then calculate each entity's average return over the 5-year period. (Hint: Remember, returns are calculated by subtracting the beginning price from the ending price to get the capital gain or loss, adding the dividend to the capital gain or loss, and dividing the result by the beginning price. Assume that dividends are already included in the index. Also, you cannot calculate the rate of return for 2009 because you do not have 2008 data.) Calculate the standard deviations of the returns for Bartman, Reynolds, and the Winslow 5000. (Hint: Use the sample standard deviation formula, Equation 8.2a in this chapter, which corresponds to the STDEV function in Excel.) b