3. A manager has been using a certain technique to forecast demand for project management software at her store. Actual demand and her corresponding predictions are shown below: Actual Demand Manager's Forecast Month March April May June July a. What was the manager's forecast error for each month? b. What is the mean error (ME), the mean squared error (MSE), the mean absolute deviation (MAD), and the tracking signal for these five months of forecasting? c. If the manager had used a 3-month moving average instead of her technique, what would have been her forecast for June and July? d. If the manager had used simple exponential smoothing with a = 0.2 instead of her technique, what would the forecast for August be, assuming that simple exponential smoothing had produced a perfectly accurate forecast in March