The Winters' additive procedure draws a graph containing the observations, predicted values, and forecasts, versus time.

The Winters' additive procedure also displays, along with the graph, the smoothing constants and three measures to help you determine the accuracy of the fitted values: MAPE, MAD, and MSD.

·    The smoothing constants (alpha, gamma, and delta) are the weights used in computing the level, trend, and seasonal components.

·    The three measures of accuracy 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 water usage data, you should fit other models and compare the accuracy measures before deciding on a final model.