a. Calculate the arithmetic average returns for large-company stocks and T-bills over this period. (Do not round intermediate calculations and round your final answer to 2 decimal places. (e.g., 32.16)) b. Calculate the standard deviation of the returns for large-company stocks and T-bills over this period. (Do not round intermediate calculations and round your final answers to 2 decimal places. (e.g., 32.16)) c-1 Calculate the observed risk premium in each year for the large-company stocks versus the T-bills. What was the arithmetic average risk premium over this period? (Negative amount should be indicated by a minus sign. Do not round intermediate calculations and round your final answer to 2 decimal places. (e.g., 32.16)) c-2 Calculate the observed risk premium in each year for the large-company stocks versus the T-bills. What was the standard deviation of the risk premium over this period? (Round your answer to 2 decimal places. (e.g., 32.16))