Calculating Returns and Variability

Youve observed the following returns on Crash-n-Burn Computers stock over the past five years: 16 percent, 5 percent, 19 percent, 13 percent, and 10 percent.

A. What was the arithmetic average return on Crash-n-Burns stock over this five-year period? (Answer is 10.6%)

B. What was the variance of Crash-n-Burns returns over this period? (87.3 is not the correct answer)

C. What was the standard deviation of Crash-n-Burns returns over this period? (Answer is 9.34%)

Any help you can provide to find the correct variance would be greatly appreciated!!