6. Risk Premiums. Here are rates of return on a broad stock market index and on Treasury bills between 2013 and 2017: L011-1) Year Stock Market Return (%) T-Bill Return (%) 0.02% 2013 31.7% 10.9 0.02 2014 2015 2016 -1.6 0.02 13.0 0.20 2017 21.3 0.80 a. What was the risk premium on common stock in each year? b. What was the average risk premium? c. What was the standard deviation of the risk premium? for 84A