> From: r-help-boun...@r-project.org
> [mailto:r-help-boun...@r-project.org] On Behalf Of Saruman
>
> I dont see how this answered the original question of the poster.
>
> He was quite clear: the value of the predictions coming out
> of RF do not
> match what comes out of the predict function u
I dont see how this answered the original question of the poster.
He was quite clear: the value of the predictions coming out of RF do not
match what comes out of the predict function using the same RF object and
the same data. Therefore, what is predict() doing that is different from RF?
Yes, RF
: Matthew Francis
> Cc: r-help@r-project.org
> Subject: Re: [R] Question about randomForest
>
> Matthew,
>
> Your intepretation of calculating error rates based on the training
> data is incorrect.
>
> In Andy Liaw's help file "err.rate-- (classification only) v
Matthew,
Your intepretation of calculating error rates based on the training
data is incorrect.
In Andy Liaw's help file "err.rate-- (classification only) vector
error rates of the prediction on the input data, the i-th element
being the (OOB) error rate for all trees up to the i-th."
My underst
I am pretty sure that when each tree is fitted the error rate for tree 'i' is
it's performance on the data which was not used to fit the ith tree (OOB). In
this way cross validation is performed for each tree but I do not think that
all trees fitted prior are involved in the computation of that
Thanks for the help. Let me explain in more detail how I think that
randomForest works so that you (or others) can more easily see the
error of my ways.
The function first takes a random sample of the data, of the size
specified by the sampsize argument. With this it fully grows a tree
resulting i
Hi Matthew,
The error rate reported by randomForest is the prediction error based
on out-of-bag OOB data. Therefore, it is different from prediction
error on the original data since each tree was built using bootstrap
samples (about 70% of the original data), and the error rate of OOB is
likely h
I've been using the R package randomForest but there is an aspect I
cannot work out the meaning of. After calling the randomForest
function, the returned object contains an element called prediction,
which is the prediction obtained using all the trees (at least that's
my understanding). I've check
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