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

Year Stock Market Return $(\%)$ T$-$Bill Return $(\%)$

$201613\mathrm{.}00\mathrm{.}2$

$201721\mathrm{.}00\mathrm{.}8$

$20186\mathrm{.}21\mathrm{.}8$

$201929\mathrm{.}82\mathrm{.}1$

$202020\mathrm{.}60\mathrm{.}4$

Required:

What was the risk premium on common stock in each year?

What was the average risk premium?

What was the standard deviation of the risk premium? $($Ignore that the estimation is from a sample of data.$)$