Re: Probabilities in Bayesian classifier

2011-06-16 Thread Svetlomir Kasabov
Hello Ted, what are the main issues of the probability estimations of the logistic regression ? I am developing a medical application for making probability estimations using time series and I that's why I would know if they are critical for me. Many thanks and best regards, Svetlomir. Am

Re: Probabilities in Bayesian classifier

2011-06-16 Thread Ted Dunning
The problem is that logistic regression makes some assumptions that are unrealistic in practice. That leads to uncalibrated probabilities in certain cases. This is particularly true where variable interactions are strong. The good news is that logistic regression gives you the best answer that

Re: Probabilities in Bayesian classifier

2011-06-16 Thread Ted Dunning
I should add that the regularization will also make the logistic regression classifier a little bit conservative about estimating probabilities near 0 or near 1. On Fri, Jun 17, 2011 at 12:19 AM, Ted Dunning ted.dunn...@gmail.com wrote: The problem is that logistic regression makes some

Re: Probabilities in Bayesian classifier

2011-06-15 Thread Svetlomir Kasabov
Hello Steven, I've asked this question too: http://mail-archives.apache.org/mod_mbox/mahout-user/201105.mbox/%3cbanlktinyohrcynt0xzrpoqqg3zkepvk...@mail.gmail.com%3E unfortunately, Mahout's Naive Bayes implemention can't calculate probabilities. You are now probably really astonished - I

Re: Probabilities in Bayesian classifier

2011-06-15 Thread Ted Dunning
This is what the term Naive is used in the name. The scores for this kind of algorithm are 0 to 1 or are logarithms of such a number, but are not at all calibrated probabilities. And, frankly, it is rare in practice for the output of logistic regression to be calibrated either. Those outputs