Eight plots (selectable by which
) are currently available:
a plot of deviance residuals against fitted values,
a non-randomized PIT histogram,
a uniform Q-Q plot for non-randomized PIT,
a histogram of the normal randomized residuals,
a Q-Q plot of the normal randomized residuals,
a Scale-Location plot of sqrt(| residuals |) against fitted values
a plot of Cook's distances versus row labels
a plot of pearson residuals against leverage.
By default, four plots (number 1, 2, 6, and 8 from this list of plots) are provided.
The 'Scale-Location' plot, also called 'Spread-Location' plot, takes the square root of
the absolute standardized deviance residuals (sqrt|E|) in order to diminish
skewness is much less skewed than than |E| for Gaussian zero-mean E.
The 'Scale-Location' plot uses the standardized deviance residuals while the
Residual-Leverage plot uses the standardized pearson residuals. They are given as
\(R_i/\sqrt{1-h_{ii}}\) where \(h_{ii}\) are the diagonal entries of the hat matrix.
The Residuals-Leverage plot shows contours of equal Cook's distance for values of 0.5
and 1.
There are two plots based on the non-randomized probability integral transformation (PIT)
using compPIT
. These are a histogram and a uniform Q-Q plot. If the
model assumption is appropriate, these plots should reflect a sample obtained
from a uniform distribution.
There are also two plots based on the normal randomized residuals calculated
using compnormRandPIT
. These are a histogram and a normal Q-Q plot. If the model
assumption is appropriate, these plots should reflect a sample obtained from a normal
distribution.