Re: [R] calculating logit parameters (odd ratio is exactly one or zero)

2011-12-13 Thread Uwe Ligges
On 13.12.2011 04:36, wim nursal wrote: Dear Uwe and David, Yes, definitely i was wrong. The expression in R should be: glm(cbind(FD, 12 - FD) ~ Fsize, family=binomial, data=subFS) Call: glm(formula = cbind(FD, 12 - FD) ~ Fsize, family = binomial, data = subFS) Coefficients:

[R] calculating logit parameters (odd ratio is exactly one or zero)

2011-12-12 Thread wim nursal
Dear statistician experts, Sorry if this is a trivial question, or the old same question (i don't know what is the efficient key word for this issue). In order to understand the calculation of parameter of logistic regression, I did an exercise through spreadsheet following the procedural

Re: [R] calculating logit parameters (odd ratio is exactly one or zero)

2011-12-12 Thread Uwe Ligges
1. The formula you used is not for a logistic but an ordinal regression (since you are using the default gaussian family rather than family=binomial or whatever. 2. R (nor any other software) can deal with perfect separation (nor quasi-separation) of classes, since the problem is not well

Re: [R] calculating logit parameters (odd ratio is exactly one or zero)

2011-12-12 Thread David Winsemius
On Dec 12, 2011, at 3:51 PM, Uwe Ligges wrote: 1. The formula you used is not for a logistic but an ordinal regression (since you are using the default gaussian family rather than family=binomial or whatever. this this then produce one version of the Armitage linear test of trend?

Re: [R] calculating logit parameters (odd ratio is exactly one or zero)

2011-12-12 Thread wim nursal
Dear Uwe and David, Yes, definitely i was wrong. The expression in R should be: glm(cbind(FD, 12 - FD) ~ Fsize, family=binomial, data=subFS) Call: glm(formula = cbind(FD, 12 - FD) ~ Fsize, family = binomial, data = subFS) Coefficients: (Intercept)Fsize 0.6381