Re: [R] logistic regression model with non-integer weights

2006-04-16 Thread Ramón Casero Cañas
Michael Dewey wrote: At 17:12 09/04/06, Ramón Casero Cañas wrote: I am not sure what the problem you really want to solve is but it seems that a) abnormality is rare b) the logistic regression predicts it to be rare. If you want a prediction system why not try different cut-offs (other

Re: [R] logistic regression model with non-integer weights

2006-04-16 Thread Rick Bilonick
On Sun, 2006-04-16 at 19:10 +0100, Ramón Casero Cañas wrote: Thanks for your suggestions, Michael. It took me some time to figure out how to do this in R (as trivial as it may be for others). Some comments about what I've done follow, in case anyone is interested. The problem is a)

Re: [R] logistic regression model with non-integer weights

2006-04-16 Thread Frank E Harrell Jr
Ramón Casero Cañas wrote: Michael Dewey wrote: At 17:12 09/04/06, Ramón Casero Cañas wrote: I am not sure what the problem you really want to solve is but it seems that a) abnormality is rare b) the logistic regression predicts it to be rare. If you want a prediction system why not try

Re: [R] logistic regression model with non-integer weights

2006-04-16 Thread Ramón Casero Cañas
Frank E Harrell Jr wrote: This makes me think you are trying to go against maximum likelihood to optimize an improper criterion. Forcing a single cutpoint to be chosen seems to be at the heart of your problem. There's nothing wrong with using probabilities and letting the utility possessor

Re: [R] logistic regression model with non-integer weights

2006-04-16 Thread Frank E Harrell Jr
Ramón Casero Cañas wrote: Frank E Harrell Jr wrote: This makes me think you are trying to go against maximum likelihood to optimize an improper criterion. Forcing a single cutpoint to be chosen seems to be at the heart of your problem. There's nothing wrong with using probabilities and

Re: [R] logistic regression model with non-integer weights

2006-04-12 Thread Michael Dewey
At 17:12 09/04/06, Ramón Casero Cañas wrote: I have not seen a reply to this so far apologies if I missed something. When fitting a logistic regression model using weights I get the following warning data.model.w - glm(ABN ~ TR, family=binomial(logit), weights=WEIGHT) Warning message:

[R] logistic regression model with non-integer weights

2006-04-09 Thread Ramón Casero Cañas
When fitting a logistic regression model using weights I get the following warning data.model.w - glm(ABN ~ TR, family=binomial(logit), weights=WEIGHT) Warning message: non-integer #successes in a binomial glm! in: eval(expr, envir, enclos) Details follow *** I have a binary dependent