The number of equally spaced points within the range
of the predictor at which the fitted model is evaluated for
plotting.
lwd, lty, col, col.line
Graphical parameters for the added
line. col.line overrides col.
type
Ignored. The argument is present only to make sure that
an explicitly specified type argument (perhaps meant for
another function) does not affect the display.
horizontal
A logical flag controlling which variable is to be treated as the
predictor (by default x) and which as the response (by
default y). If TRUE, the plot is ‘transposed’
in the sense that y becomes the predictor and x the
response. (The name ‘horizontal’ may seem an odd choice for
this argument, and originates from similar usage in
bwplot).
keep.data
Passed on to smooth.spline. The
default here (FALSE) is different, and results in the
original data not being retained in the fitted spline model. It may
be useful to set this to TRUE if the return value of
panel.spline, which is the fitted model as returned by
smooth.spline, is to be used for subsequent
computations.
...
Extra arguments, passed on to
smooth.spline and panel.lines as
appropriate.
identifier
A character string that is prepended to the names of grobs
that are created by this panel function.