Consider the following table for the period from $1973$ through $1980.$

Answer is complete but not entirely correct.

a$.$ Calculate the average return for Treasury bills and the average annual inflation rate

$($consumer price index$)$ for this period. $($Do not round intermediate calculations and

enter your answers as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

b$.$ Calculate the standard deviation of Treasury bill returns and inflation over this time

period. $($Do not round intermediate calculations and enter your answers as a

percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

c$.$ Calculate the real return for each year. $($A negative answer should be indicated by a

minus sign. Do not round intermediate calculations and enter your answers as a

percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

d$.$ What is the average real return for Treasury bills? $($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$.,32\mathrm{.}16.)$