You've observed the following returns on Yamauchi Corporation's stock over the past five years: -25.5 percent, 14 percent, 31 percent, 2.5 percent, and 21.5 percent. a. What was the arithmetic average return on the stock over this five-year period? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) b. What was the variance of the returns over this period? (Do not round intermediate calculations and round your answer to 6 decimal places, e.g., 32.161616.) c. What was the standard deviation of the returns over this period? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) Arithmetic average return . b. Variance Standard deviation