Consider the following table for a period of six years: Returns U.S. Treasury Year Large-Company Stocks Bills 123 -15.69% 7.49% -26.77 8.09 37.43 6.07 4 24.13 6.07 5 -7.56 5.55 6 6.77 7.94 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., 32.16. 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., 32.16. Large-company stocks T-bills a-1. Arithmetic average return % % a-2. Standard deviation % % 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., 32.16. b-2. What was the standard deviation of the risk premium over this period? Note: Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16. b-1. Average risk premium b-2. Risk premium standard deviation % %