You've observed the following returns on Crash-n-Burn Computer's stock over the past five years: 20 percent, -12 percent, 17 percent, 20 percent, and 10 percent. a. What was the arithmetic average return on Crash-n-Burn's stock over this five-year period? Average return % b. What was the variance of Crash-n-Burn's returns over this period? Variance = c. What was the standard deviation of Crash-n-Burn's returns over this period? Standard deviation %