You find a certain stock that had returns of 13 percent, - 18 percent, 9 percent, and

Question:

You find a certain stock that had returns of 13 percent, - 18 percent, 9 percent, and 36 percent for four of the last five years. If the average return of the stock over this period was 11 percent, what was the stock’s return for the missing year? What is the standard deviation of the stock’s returns?