You've observed the following returns on SkyNet Data Corporation'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 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.)

b1. What was the variance of the stock's returns over this period?

(Do not round intermediate calculations and round your answer to 5 decimal places, e.g., 32.16161.)

b2. What was the standard deviation of the stock'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.)