The last four years of returns for a stock are as follows: Year Return 1 - 3.8% 2 27.9% 3 12.5% 4 3.7% a. What is the average annual return? b. What is the variance of the stock's returns? c. What is the standard deviation of the stock's returns? ---- a. What is the average annual return? The average return is %. (Round to two decimal places.) %