The diagnostics required for the plots are calculated by
rsm.diag
. These are then used to produce the plots
on the current graphics device.
A menu lists all the plots that can be produced. They may be one or
all of the following:
Make a plot selection (or 0 to exit)1: All
2: Response residuals against fitted values
3: Deviance residuals against fitted values
4: QQ-plot of deviance residuals
5: Normal QQ-plot of r* residuals
6: Cook statistic against h/(1-h)
7: Cook statistic against observation number
Selection:
In the normal scores plots, the dotted line represents the expected
line if the residuals are normally distributed, i.e. it is the line
with intercept 0 and slope 1.
In general, when plotting Cook's distance against the standardized
leverages, there will be two dotted lines on the plot. The
horizontal line is at \(8/(n-2p)\), where \(n\) is
the number of observations and \(p\) is the number of
estimated parameters. Points above this line may be points with
high influence on the model. The vertical line is at
\(2p/(n-2p)\) and points to the right of this line have
high leverage compared to the variance of the raw residual at that
point. If all points are below the horizontal line or to the left
of the vertical line then the line is not shown.
Use of iden = TRUE
is encouraged for proper exploration of
these plots as a guide to how well the model fits the data and
whether certain observations have an unduly large effect on
parameter estimates.