Consider the following table for a period of six years: Returns U.S. Treasury Year Large-Company Stocks Bills 123456 -15.69% -26.77 37.43 7.49% 8.09 6.07 24.13 6.07 5.55 7.94 -7.56 6.77 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. a-1. Arithmetic average return a-2. Standard deviation Large-company stocks T-bills % % % %