At 01:45 PM 30/06/2005, Young Cho wrote: >Hi, I am trying to find out a collinearity in >explanatory variables with alias(). > >I creat a dataframe: > >dat <- ds[,sapply(ds,nlevels)>=2] >dat$Y <- Response > >Explanatory variables are factor and response is >continuous random variable. When I run a regression, I >have the following error: > >fit <- aov( Y ~ . , data = dat) >Error in "contrasts<-"(`*tmp*`, value = >"contr.treatment") : > contrasts can be applied only to factors with >2 or more levels
1. Sounds like at least one of your factors has only one level. This should be easy to spot. 2. Have you considered package perturb? HTH, Simon. >I think there is a dependency in explanatory >variables. So, I wanted to use alias to find out a >dependency in design matrix but I can't because I >cannot create "fit" in the first place. > >One of examples I found is: > >carprice1.lm <- lm(gpm100 ~ >Type+Min.Price+Price+Max.Price+Range.Price,data=carprice) >alias(carprice1.lm) > >But, what if I can create lm object ? Then is there a >way to find out a dependency in design matrix? Thanks >a lot for help in advance! > >-Young. > >______________________________________________ >R-help@stat.math.ethz.ch mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Simon Blomberg, B.Sc.(Hons.), Ph.D, M.App.Stat. Centre for Resource and Environmental Studies The Australian National University Canberra ACT 0200 Australia T: +61 2 6125 7800 email: Simon.Blomberg_at_anu.edu.au F: +61 2 6125 0757 CRICOS Provider # 00120C ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html