One of the dominant features of many economic and business time series is the trend. Such a trend can be upward or downward, it can be steep or not, and it can be exponential or approximately linear. A trend should be incorporated in a time series model, because it can be exploited for the forecasting.
One of the dominant features of many economic and business time series is the trend. Such a trend can be upward or downward, it can be steep or not, and it can be exponential or approximately linear. A trend should be incorporated in a time series model, because it can be exploited for the forecasting. (en)