You've observed the following returns on Pine Computer's stock over the past five years: 12 percent, -9 percent, 20 percent, 17 percent, and 10 percent. a. What was the arithmetic average return on the company's stock over this five-year period? (Do not round intermediate calculations and enter your answer as a percent rounded to 1 decimal place, e.g., 32.1.) b-1. What was the variance of the company's returns over this period? (Do not round intermediate calculations and round your answer to 5 decimal places, e.g., .16161.) b-2. What was the standard deviation of the company's 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.)