ROC Curves !

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ROC Curves !

Praveen Boinee
Dear WEKA People

1) How to plot multiple ROC 's on single plot ... I see nice graphics
roc plot in WEKA for individual classifiers
is thery any way to put all the ROC's in one plot

2) I want to compare MLP with SVM and random forests
   my test set has 6400 rows ...i am using the explorer in WEKA
I can see the False positive rate[FPR]  and true pos.rate[TPR] for all
6400 rows only in MLP !! With SVM there  only 2 rows  of FPR and TPR and
with random forests only 30 rows  of FPR and TPR  ..

       is it common to get like this ..!!

P.S. Sorry of u recieve this message multiple times

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Re: ROC Curves !

Eibe Frank

On May 11, 2005, at 8:49 PM, Praveen Boinee wrote:

> Dear WEKA People
>
> 1) How to plot multiple ROC 's on single plot ... I see nice graphics
> roc plot in WEKA for individual classifiers
> is thery any way to put all the ROC's in one plot

You can do that using the KnowledgeFlow interface.

> 2) I want to compare MLP with SVM and random forests
>   my test set has 6400 rows ...i am using the explorer in WEKA
> I can see the False positive rate[FPR]  and true pos.rate[TPR] for all
> 6400 rows only in MLP !! With SVM there  only 2 rows  of FPR and TPR
> and with random forests only 30 rows  of FPR and TPR  ..
>
>       is it common to get like this ..!!

You need to use the -M option (i.e. fit logistic models) to get less
discrete "probability estimates" (the standard ones are based on votes,
i.e. 0/1 in the two-class case). Random forests produce pretty discrete
distributions because standard trees do. You might be able to get more
points by increasing the number of iterations.

Cheers,
Eibe


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