Assume these are the stock market and Treasury bill returns for a 5-year period: Required: a. What was the risk premium on common stock in each year? (Negative values should be entered with a negative sign.) b. What was the average risk premium? c. What was the standard deviation of the risk premium? (Ignore that the estimation is from a sample of data.) Complete this question by entering your answers in the tabs below. What was the risk premium on common stock in each year? (Do not round intermediate calculations. percent rounded to 2 decimal places.)