Problem 18-18 (Algo) A particular forecasting model was used to forecast a six-month period. Here are the forecasts and actual demands that resulted: FORECAST ACTUAL April 244 195 May 318 254 June 393 338 July 343 296 August 368 334 September 443 403 a. Find the tracking signal for each month. (Negative values should be indicated by a minus sign. Round your answers to the nearest whole number.) Month Tracking Signal April May June July August September b. Does the model used here give acceptable answers? O No, the model's performance is poor. O Yes, the model's performance is good.