Joshua B Robins wrote: > Hello, > > I'm trying to figure out how to run the stepAIC function starting with the > NULL model. I can call the null model (e.g., lm(y ~ NULL)), but using > this object in stepAIC doesn't seem to work. > I don't know what "doesn't seem to work" means here, but your null model is equivalent to lm(y ~ 1) and stepAIC handles both just fine for me. Did you specify 'scope' with an 'upper' component?
Peter Ehlers > The objective is to calculate AICc. This can be done if stepAIC can be > run starting with the NULL model; the (2p(p-1)/(n-p-1))to get AICc would > be added to the final step AIC value. Can anyone suggest how to run > stepAIC beginning with the NULL model, and sequentially adding and > removing variables (essentially a bottom-up approach)? > > Thanks, > > Josh Robins > School of Fisheries and Ocean Sciences > University of Alaska Fairbanks > Juneau Center > (206) 331-8633 > [EMAIL PROTECTED] > http://students.washington.edu/jbrobins > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
