Leafrates for the Nodes of an 'rpart' Tree

Return the frequencies of correct and wrong classifications in given node(s) in tabular form. The 'purity', denoting the relative frequency of correctly classified elements, is a useful information for the interpretation of regression and classification trees and a measure for its quality.

Usage

LeafRates(x)

# S3 method for class 'LeafRates'
plot(x, col = NULL, which = c("rel", "abs"),
                         layout = NULL, ylim = NULL, ...)

Arguments

x: fitted model object of class rpart.
col: color for the bars in the plot
which: one out of "rel" or "abs", denoting whether relative or absolute frequencies should be used for the plot.
layout: vector defining the layout
ylim: the y limits of the plot.
...: further arguments (not used).

Details

The result comprises absolute and relative frequencies per leaf.

Value

A list with 5 elements consisting of:

node: the node id (of the leaf)
freq: the absolute frequency of correct and wrong classifications
p.row: the relative frequency of correct and wrong classifications
mfreq: the total number of cases
mperc: the percentage of the sample in the leaf

Author

Andri Signorell <andri@signorell.net>

Examples

r.rp <- FitMod(Species ~ ., data=iris, fitfn="rpart")
LeafRates(r.rp)
#>        freq          perc          total        
#> node   right  wrong  right  wrong  abs    perc  
#>                                                 
#> 2      50     0      100.0% 0.0%   50     33.3% 
#> 6      49     5      90.7%  9.3%   54     36.0% 
#> 7      45     1      97.8%  2.2%   46     30.7% 

plot(LeafRates(r.rp))