Message-ID: <42F1C77B.5000002@statistik.uni-dortmund.de>
Date: 2005-08-04T07:44:59Z
From: Uwe Ligges
Subject: Puzzled at rpart prediction
In-Reply-To: <20050804010321.GA17700@lubyanka.local>
Ajay Narottam Shah wrote:
> I'm in a situation where I say:
>
>
>>predict(m.rpart, newdata=D[N1+t,])
>
> 0 1
> 173 0.8 0.2
>
> which I interpret as meaning: an 80% chance of "0" and a 20% chance of
> "1". Okay. This is consistent with:
>
>
>>predict(m.rpart, newdata=D[N1+t,], type="class")
>
> [1] 0
> Levels: 0 1
>
> But I'm puzzled at the following. If I say:
>
>
>>predict(m.rpart, newdata=D[N1+t,], type="vector")
>
> 173
> 1
>
> What gives?
This means that the class of the first level is chosen, and the first
level is "0".
Uwe Ligges
> I will be happy to packup a runnable demonstration for any of you, but
> I wondered if it was just my lack of knowledge about "type" in
> predict.rpart; wondered if there was a simple and logical explanation.
>