Minitab displays three measures of the accuracy of the fitted values:

·    MAPE (Mean Absolute Percent Error) - measures the accuracy of fitted time series values and expresses it as a percentage.

·    MAD (Mean Absolute Deviation) - measures the accuracy of fitted time series values and expresses it in the same units as the data, which helps conceptualize the amount of error.

·    MSD (Mean Squared Deviation) - measures the accuracy of fitted time series values. MSD is always computed using the same denominator (the number of forecasts) regardless of the model, so you can compare MSD values across models and therefore you can compare the accuracy of two different models.

The three measures are not very informative by themselves, but they are used to compare the fits obtained by using different methods. For all three measures, smaller values generally indicate a better fitting model.

For the sales data, you should fit other models and compare the accuracy measures before deciding on a final model.