Large-Company Year Stocks U.S. Treasury Bills I -15.79 7.51% -26.80 8.10 3 37.45 6.09 24.15 6.17 -7.60 5.56 6.79 7.97 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. Answer is complete but not entirely correct. a-1. Arithmetic average return a-2. Standard deviation Large-company stocks 3.03 % 22.33% T-bills 6.90 % 1.00%