[R] RandomForest question

[Uwe Ligges]

Arne.Muller at sanofi-aventis.com wrote:

> Hello,
> 
> I'm trying to find out the optimal number of splits (mtry parameter)
> for a randomForest classification. The classification is binary and
> there are 32 explanatory variables (mostly factors with each up to 4
> levels but also some numeric variables) and 575 cases.
> 
> I've seen that although there are only 32 explanatory variables the
> best classification performance is reached when choosing mtry=80. How
> is it possible that more variables can used than there are in columns
> the data frame?

If some of the variables are factors, dummy variables are generated and 
you get a larger number of variables in the later process.

Uwe Ligges


> thanks for your help + kind regards,
> 
> Arne
> 
> 
> 
> 
> [[alternative HTML version deleted]]
> 
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