Forecasting time series
forecast is a generic function for forecasting from time series or time series models.
The function invokes particular methods which depend on the class of the first argument.
For example, the function
forecast.Arima makes forecasts based on the results produced by
forecast.ts makes forecasts using exponential smoothing state space models.
forecast(object,...) ## S3 method for class 'ts': forecast(object, h, level=c(80,95), fan=FALSE, ...)
- a time series or time series model for which forecasts are required
- Number of periods for forecasting
- Confidence level for prediction intervals.
- If TRUE, level is set to seq(50,99,by=1). This is suitable for fan plots.
- Additional arguments affecting the forecasts produced.
forecast.tspasses these to
The default behaviour is to use a model estimated using
- An object of class "
forecast". The function
summaryis used to obtain and print a summary of the results, while the function
plotproduces a plot of the forecasts and prediction intervals. The generic accessor functions
residualsextract various useful features of the value returned by
forecast$model. An object of class
"forecast"is a list containing at least the following elements:
model A list containing information about the fitted model method The name of the forecasting method as a character string mean Point forecasts as a time series lower Lower limits for prediction intervals upper Upper limits for prediction intervals level The confidence values associated with the prediction intervals x The original time series (either
objectitself or the time series used to create the model stored as
residuals Residuals from the fitted model. That is x minus fitted values. fitted Fitted values (one-step forecasts)