Problem $11-6$ Risk Premiums $($LO$1)$

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

$\backslash$table$[[$Year$,$Stock Market Return $(\%),$T$-$Bill Return $(\%)],[2016,13\mathrm{.}0,0\mathrm{.}2],[2017,21\mathrm{.}0,0\mathrm{.}8],[2018,-6\mathrm{.}2,1\mathrm{.}8],[2019,29\mathrm{.}8,2\mathrm{.}1],[2020,20\mathrm{.}6,0\mathrm{.}4]]$

Required:

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? $($Ignore that the estimation is from a sample of data.$)$