[R] lda of MASS library

About this list Date view Thread view Subject view Author view Attachment view

From: array chip (arrayprofile@yahoo.com)
Date: Wed 02 Apr 2003 - 12:06:33 EST


Message-id: <20030402020633.63539.qmail@web41206.mail.yahoo.com>


Hi,

it seems that the lda function in MASS library doesn't give out the constant for the linear discriminant function under the situation that we don't use standardized variable, anyone knows how to obtain the constant in order to construct the linear discriminant function?

I understand that if the priors are set to be 1/2, the threshold of the discriminant score used to separate the 2 classes is 0, how about if the priors are not 1/2 vs. 1/2, e.g. like 1/3 vs. 2/3, in this situation, how to determine a threshold of the discriminant score to separate the 2 classes? Is there a simple formula existing? I understand posterior probabilities are usually used for classification, but I would like to know if I want to use discriminant scores, how can I do it?

Thank you

---------------------------------

        [[alternate HTML version deleted]]

______________________________________________
R-help@stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help


About this list Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.3 : Tue 01 Jul 2003 - 09:11:35 EST