What if the last two decades had been normal? Download the spreadsheet from MyFinanceLab containing the data

Question:

What if the last two decades had been “normal”? Download the spreadsheet from MyFinanceLab containing the data for Figure 10.1.
a. Calculate the arithmetic average return on the S&P 500 from 1926 to 1989.
b. Assuming that the S&P 500 had simply continued to earn the average return from (a), calculate the amount that $100 invested at the end of 1925 would have grown to by the end of 2011.
c. Do the same for small stocks.