Problem 10-9 Calculating Returns and Variability You've observed the following returns on Mary Ann Data Corporation's stock over the past five years: 15 percent, -15 percent, 17 percent, 27 percent, and 10 percent. a. What was the arithmetic average return on Mary Ann's stock over this five-year period? (Do not round intermediate calculations and round your final answer to 2 decimal places. (e.g., 32.16) Average return b-1. What was the variance of Mary Ann's returns over this period? (Do not round intermediate calculations and round your answer to 5 decimal places. (e.g., 32.16161)) Variance b-2. What was the standard deviation of Mary Ann's returns over this period? (Do not round intermediate calculations and round your final answer to 2 decimal places. (e.g., 32.16)) Standard deviation