plotcp {rpart} | R Documentation |
Gives a visual representation of the cross-validation results in an
rpart
object.
plotcp(x, minline = TRUE, lty = 3, col = 1, upper = c("size", "splits", "none"), ...)
x |
an object of class |
minline |
whether a horizontal line is drawn 1SE above the minimum of the curve. |
lty |
line type for this line |
col |
colour for this line |
upper |
what is plotted on the top axis: the size of the tree (the number of leaves), the number of splits or nothing. |
... |
additional plotting parameters |
The set of possible cost-complexity prunings of a tree from a nested
set. For the geometric means of the intervals of values of cp
for which
a pruning is optimal, a cross-validation has (usually) been done in
the initial construction by rpart
. The cptable
in the fit contains
the mean and standard deviation of the errors in the cross-validated
prediction against each of the geometric means, and these are plotted
by this function. A good choice of cp
for pruning is often the
leftmost value for which the mean lies below the horizontal line.
None.
A plot is produced on the current graphical device.