a character string specifying the type of residuals used in the plot. This argument is passed to the generic residuals function when extracting the residuals from x.
level
a numeric value between 0 and 1 specifying the confidence level used to draw the threshold in the plot.
id.n
a non-negative integer value specifying the number of extreme points to identify.
main
a character string specifying the plot title.
xlab
a character string specifying the x-axis label.
ylab
a character string specifying the y-axis label.
...
additional arguments are passed to the low-level plotting functions.