over the past five years, a stock returned 8.7 percent, -31.9 percent, -2.4 percent, 46.1 percent, and 12 percent, respectively. what is the average return? what is the variance of these returns?

Over the past five years, a stock returned 8.7 percent, 31.9 percent, 2.4 percent, 46.1 percent, and 12 percent, respectively. What is the average return? What is the variance of these returns