Re: [R] lrm -interaction without main effect-error message

2008-04-01 Thread Frank E Harrell Jr
Eva Mosner wrote: > Dear all, > > this might be not only an R-question but also a statistical. > When I do a logistic regression analysis (species distribution modeling) > with function lrm (Design package) I get the follwoing error message: > > > tadl1<-lrm(triad~fd+dista+fd2+dista2+fd:dista+d

[R] lrm -interaction without main effect-error message

2008-04-01 Thread Eva Mosner
Dear all, this might be not only an R-question but also a statistical. When I do a logistic regression analysis (species distribution modeling) with function lrm (Design package) I get the follwoing error message: > tadl1<-lrm(triad~fd+dista+fd2+dista2+fd:dista+dista:geo2, x=T, y=T) Error in i