Uwe -On my email editor, it shows the break line properly as I don't think I can type in one straight line without break as it shows from your reply. My apology if this causes you inconvenience. I think it's just the text got transformed improperly between systems.The dat is simply a predefined data.frame which I populate value previous to calling of this line. I'm using MASS 7.2-33. And my OS is windows Vista. Thank you.- adschai----- Original Message -----From: Uwe Ligges Date: Tuesday, June 5, 2007 2:05 amSubject: Re: [R] Question using stepAICTo: adschai@optonline.netCc: r-help@stat.math.ethz.ch> > > adschai@optonline.net wrote:> > Hi - I use stepAIC to automatically select the model. The > stepAIC was applied on polr as follow:objPolr <- > polr(formula=myformula, data=dat, method=METHOD);objPolr.step <- > stepAIC(objPolr, trace=T);Then R complaints that it doesn't know > about 'dat' when it executes the second line. Below is the exact > error that I got when executing the stepAIC line above:Error in > eval(expr, envir, enclos) : object "dat" not foundWould you > please provide some guide to circumvent this? Thank you.- adschai> > > Please read the psoting guide mentioned below each message of > this list > and learn to add appropriate line breaks to your messages or fix > your > Enter key.> > What is dat? Is it a data.frame in the Workspace? What R > version, what > version of MASS, which OS?> > Uwe Ligges> > > > > 	[[alternative HTML version deleted]]> > > > ______________________________________________> > 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> > and provide commented, minimal, self-contained, reproducible code.>

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