[R] Repost: Examples of "classwt", "strata", and "sampsize" in randomForest?

[Gabor Grothendieck]

See
http://finzi.psych.upenn.edu/R/Rhelp02a/archive/40898.html

On 10/27/05, David L. Van Brunt, Ph.D. <dlvanbrunt at gmail.com> wrote:
> Sorry for the repost, but I've really been looking, and can't find any
> syntax direction on this issue...
>
> Just browsing the documentation, and searching the list came up short... I
> have some unbalanced data and was wondering if, in a "0" v "1"
> classification forest, some combo of these options might yield better
> predictions when the proportion of one class is low (less than 10% in a
> sample of 2,000 observations).
>
> Not sure how to specify these terms... from the docs, we have:
>
> classwt: Priors of the classes. Need not add up to one. Ignored for
> regression.
>
> So is this something like "... classwt=c(.90,.10)" ? I didn't see the syntax
> demonstrated. Similar for "strata" and "sampsize" though there is a default
> for sampsize that makes sense... not sure how you would make "a vector of
> the length the number of strata", however....
>
> Pointers?
>
> --
> ---------------------------------------
> David L. Van Brunt, Ph.D.
> mailto:dlvanbrunt at gmail.com
>
> --
> ---------------------------------------
> David L. Van Brunt, Ph.D.
> mailto:dlvanbrunt at gmail.com
>
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