After using your forecasting model for six months, you decide to test it using a tracking signal. Here are the forecast and actual demands for the six-month period: ACTUAL 500 PERTOD May June July August September October PORECAST 445 495 545 610 660 690 530 400 470 685 a. Find the tracking signal. (Negative values should be indicated by a minus sign. Round your answers to 2 decimal places.) Period Tracking Signal May June July August September October