calculate the average return for treasury bills and the average annual inflation rate for this period. (do not round intermediate calculations and enter your answers as a percent rounded to 2 decimal places, e.g., 32.16.)b. calculate the standard deviation of treasury bill returns and inflation over this period. (do not round intermediate calculations and enter your answers as a percent rounded to 2 decimal places, e.g., 32.16.)c. what was the average real return for treasury bills over this period? (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., 32.16.)