Assume these are the stock market and Treasury bill returns for a 5-year period Stock Market T-Bill Return (%) Year Return 2011 -34.63 3.90 0.30 0.25 2012 2013 31.40 14.86 2014 3.08 0.10 0.12 2015 19.26 a. What was the risk premium on common stock in each year? (Do not round intermediate calculations. Enter your answers as a percent rounded to 2 decimal places.) Year Risk Premium 2011 2012 2013 2014 2015 b. What was the average risk premium? (Do not round intermediate calculations. Enter your answer as a percent rounded to 2 decimal places.) Average risk premium c. What was the standard deviation of the risk premium? (Do not round intermediate calculations. Enter your answer as a percent rounded to 2 decimal places.) Standard deviation