weka - what is the cause of Accuracy difference? -

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i have dataset of 2001 attribute , 63 instances while doing classification using weka can see j48 have higher accuracy compared naive bayes.but after doing pca can see j48 accuracy decrease compared first 1 first got 82% , after pca got 72.5%.what reason?

decision trees select features.

pca mixes features components.

this makes feature selection work less - every input feature influences (almost) every derived feature.

don't assume pca magic tool solves problems. can work - can make things worse.


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