[R] rpart.object help

[Gavin Simpson]

On Mon, 2010-12-13 at 01:55 -0800, jagdeesh_mn wrote:
> 
> Prof Brian Ripley wrote:
<snip />
> 
> Thanks Mr. Brian. That kind of answers my query. 
> 
> On the same note I would like to ask few other questions. Sorry if you find
> them naive, I am a novice in this subject and am trying to get a grip on
> things. 
> 
> 1. I am using R package using my code and the fitted object looks like this
> :
> 
> The Model representation :
> n= 60 
> 
> node), split, n, deviance, yval
>       * denotes terminal node
> 
>  1) root 60 983551500 12615.670  
>    2) dataFrame[, 6]='Small' 13  21804710  7682.385 *
>    3) dataFrame[, 6]='Compact','Large','Medium','Sporty','Van' 47 557851600
> 13980.190  
>      6) dataFrame[, 3]='Japan/USA','Korea','USA' 29 131050000 12673.030  
>       12) dataFrame[, 6]='Compact','Sporty' 14  11426050 11055.570 *
>       13) dataFrame[, 6]='Large','Medium','Van' 15  48812470 14182.670 *
>      7) dataFrame[, 3]='France','Germany','Japan','Sweden' 18 297418200
> 16086.170 * 
> 
> What does the term deviance here stand for?

At this point, go an read up on the theory of classification and
regression trees. Depending on how you fitted your tree (what options
used, what type of response modelled) the deviance could be computed in
different ways. In short it is a measure of how impure each node of the
tree is.

See the References section of ?rpart

HTH

G

> 2. Could you also suggest me some readings on the topic of CnR trees
> specific to R with case studies?
> 
> Regards,
> Jagdeesh

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