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

From: David L. Van Brunt, Ph.D. <dlvanbrunt_at_gmail.com>
Date: Tue 25 Oct 2005 - 14:50:02 EST


Just browsing the documentation, and searching the list came up short... I have some unbalance data and was wondering if, in a "0" v "1" classification forest, if 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@gmail.com

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