Here are stock market and Treasury bill returns between 1997 and 2001:

Year: 1997 Stock Market Return= 31.29 T-Bill Return = 5.26
Year: 1998 Stock Market Return = 23.43 T-Bill Return = 4.86
Year: 1999 Stock Market Return = 23.56 T-Bill Return = 4.68
Year: 2000 Stock Market Return = -10.89 T-Bill Return = 5.89
Year: 2001 Stock Market Return = -10.97 T-Bill Return = 3.83

a. Determine the risk premium on common stock in each year?
b. Determine the average risk premium?
c. Determine the standard deviation of the risk premium?