Assume these are the stock market and Treasury bill returns for a 5-year period:

Year	Stock Market Return (%)	T-Bill Return (%)
2016	35.60	0.20
2017	15.10	0.20
2018	5.00	0.20
2019	16.70	0.07
2020	25.50	0.09

Required:

1. What was the risk premium on common stock in each year?
2. What was the average risk premium?
3. What was the standard deviation of the risk premium? (Ignore that the estimation is from a sample of data.)