Re: [R] logistic regression: wls and unbalanced samples

2011-04-27 Thread Andre Guimaraes
Many thanks for your messages. I will take a look at the survey package. I was concerned with the issues raised by Cramer (1999) in "Predictive performance of the binary logit model in unbalanced samples". In this particular case, misclassification costs are much higher for the smaller group (def

Re: [R] logistic regression: wls and unbalanced samples

2011-04-27 Thread Prof Brian Ripley
On Wed, 27 Apr 2011, peter dalgaard wrote: On Apr 27, 2011, at 00:22 , Andre Guimaraes wrote: Greetings from Rio de Janeiro, Brazil. I am looking for advice / references on binary logistic regression with weighted least squares (using lrm & weights), on the following context: 1) unbalanced s

Re: [R] logistic regression: wls and unbalanced samples

2011-04-27 Thread peter dalgaard
On Apr 27, 2011, at 00:22 , Andre Guimaraes wrote: > Greetings from Rio de Janeiro, Brazil. > > I am looking for advice / references on binary logistic regression > with weighted least squares (using lrm & weights), on the following > context: > > 1) unbalanced sample (n0=1, n1=700); > 2) s

[R] logistic regression: wls and unbalanced samples

2011-04-26 Thread Andre Guimaraes
Greetings from Rio de Janeiro, Brazil. I am looking for advice / references on binary logistic regression with weighted least squares (using lrm & weights), on the following context: 1) unbalanced sample (n0=1, n1=700); 2) sampling weights used to rebalance the sample (w0=1, w1=14.29); e 3) a