1

j48 weka

Hi, I have problem with my model in weka (j48 cross-validation) that many instances are classified wrong when it comes to the second class. Is there any way to improve it or rather not? I'm not an expert in weka. Thank you in advance. My output is above. In NaiveBayes it presents better but still TP Rate < 0.5 for the second class. NaiveByes weka

Sabina
  • 25
  • 1
  • 1
  • 6
  • may be you can reach a better model if you clean your data or define new features which can describe better your data. – Istvan Nagy Feb 16 '16 at 12:33

1 Answers1

1

It is hard to reproduce your example with the given information. However the solution is probably to turn your classifiert into a cost sensitive classifier https://weka.wikispaces.com/CostSensitiveClassifier?responseToken=019a566fb2ce3b016b9c8c791c92e8e35

What it does it assigns a higher value to misclassifications of a certain class. In your case this would be the "True" class.

You can also simulate such an algorithm by oversampling your positive examples. This is, if you have n positive examples you sample k*n positive example, while you keep your negative examples as they are. You could also simply double positive examples.

CAFEBABE
  • 3,983
  • 1
  • 19
  • 38