You've observed the following returns on Mary Ann Data Corporation's stock over the past five years: 34.50 percent, 16.50 percent, 19.50 percent, -21.50 percent, and 8.50 percent. a. What was the arithmetic average return on Mary Ann's stock over this five-year period? (Do not round intermediate calculations. Round the final answer to 2 decimal places.) Arithmetic average return 7 % b-1. What was the variance of Mary Ann's returns over this period? (Do not round intermediate calculations. Round the final answer to 6 decimal places.) Variance b-2. What was the standard deviation? (Do not round intermediate calculations. Round the final answer to 2 decimal places.) Standard deviation