I know the first answer is 11.80%. Can you help me find the answer to part A and B?

You've observed the following returns on Doyscher Corporation's stock over the past five years: -12 percent, 21 percent, 27 percent, 6 percent, and 17 percent. Requirement 1: What was the arithmetic average return on the stock over this five-year period? (Do not round intermediate calculations. Enter your answer as a percentage rounded to 2 decimal places (e.g., 32.16).) Arithmetic average return 11.8 % Requirement 2: (a) What was the variance of the returns over this period? (Do not round intermediate calculations. Enter your answer as a percentage rounded to 6 decimal places (e.g., 32.161616).) Variance (b) What was the standard deviation of the returns over this period? (Do not round intermediate calculations. Enter your answer as a percentage rounded to 2 decimal places (e.g., 32.16).) Standard deviation