A series of measurements over time, usually at regular intervals, of a random variable. A prime concern is the forecasting of future values using methods such as exponential smoothing, Holt–Winters forecasting, or Box–Jenkins methods. Models fitted include autoregressive models and moving average models. It is often necessary to deseasonalize the data and to remove any underlying trend before undertaking the analysis. See also periodogram.
Time series. The famous series illustrated shows the variation in the numbers of lynx trapped in the neighbourhood of the Mackenzie River, in Canada, for the years 1821 to 1934. The numbers of lynx vary according to the amount of food available. A major component of this food is the snowshoe hare, which shows a similar cycle: a rise in the lynx population leads to a fall in the hare population, which leads to a fall in the lynx population, which leads to a rise in the hare population, and so on.
