You find a certain stock that had returns of 15 percent, -17 percent, 23 percent, and 11 percent for four of the last five years. Assume the average return of the stock over this period was 10 percent. a. What was the stock's return for the missing year? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) b. What is the standard deviation of the stock's returns? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) a. Missing return |Standard b. deviation