Consider the following table for a period of six years: Year Returns Large- U.S. Company Treasury Bills Stocks - 14.89% 7.33% -26.53 8.01 37.27 5.91 23.97 5.27 - 7.24 5.47 6.61 7.70 nm to a-1. Calculate the arithmetic average returns for large-company stocks and T-bills over this time period. (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. (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