tsdiag.Arima: Model Diagnostics for a Fitted ARIMA Model
Description
This function is modified from the tsdiag function of the
stats package.
Usage
# S3 method for Arima
tsdiag(object, gof.lag, tol = 0.1, col = "red", omit.initial = TRUE,...)
Arguments
object
a fitted ARIMA model
gof.lag
maximum lag used in ACF and Ljung-Box tests for the residuals
tol
tolerance (default=0.1); see below
col
color of some warning lines in the figures (default=red)
omit.initial
suppress the initial (d+Ds) residuals if true
...
other arguments to be passed to the acf function
Value
Side effects:
Plot the time plot of the standardized residuals. Red dashed line at
+/-qnorm(0.025/no of data) are added to the plot. Data beyond these lines are deemed outliers,
based on the Bonferronni rule.
The ACF of the standardized residuals is plotted.
The p-values of the Ljung-Box test are plotted using a variety of
the first K residuals. K starts at the lag on and beyond which the
moving-average weights (in the MA(infinity) representation)
are less than tol.