Consider the following table for a period of six years:

Year Returns

Large$-$Company Stocks U$.$S$.$ Treasury Bills

$115\mathrm{.}79\%7\mathrm{.}51\%$

$226\mathrm{.}808\mathrm{.}10$

$337\mathrm{.}456\mathrm{.}09$

$424\mathrm{.}156\mathrm{.}17$

$57\mathrm{.}605\mathrm{.}56$

$66\mathrm{.}797\mathrm{.}97$

a$-1.$ Calculate the arithmetic average returns for large$-$company stocks and T$-$bills over this time period.

Note: Do not round intermediate calculations and enter your answers as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

a$-2.$ Calculate the standard deviation of the returns for large$-$company stocks and T$-$bills over this time period.

Note: Do not round intermediate calculations and enter your answers as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

Calculate the observed risk premium in each year for the large$-$company stocks versus the T$-$bills.

b$-1.$ What was the arithmetic average risk premium over this period?

Note: A negative answer should be indicated by a minus sign. Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

b$-2.$ What was the standard deviation of the risk premium over this period?