You've observed the following returns on Bennington Corporation's stock over the past five years: 18 percent, -3 percent, 16 percent, 11 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 stock returns over this period? (Do not round intermediate calculations and round your answer to 5 decimal places, e.g., .32161 \). b-2. What was the standard deviation of the company's stock 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.)