Hi Saiwing, If all you are asking is how to rename a factor vector, the easiest way would be to use: levels(Loblolly$Seed) <- c( a vector of level names you would like to use for the factor - separated by commas)
If you are asking how to make your output look better, I am not sure I have an idea (except for using "summary(fit)" - but I guess that is not what you mean) Best, Tal On Sat, Mar 21, 2009 at 11:02 PM, Saiwing Yeung <saiw...@berkeley.edu>wrote: > Hi all, > > I have a pretty basic question about categorical variables but I can't seem > to be able to find answer so I am hoping someone here can help. I found that > if the factor names are all in numbers, fitting the model in lm would return > labels that are not very recognizable. > > # Example: let's just assume that we want to fit this model > fit <- lm(height ~ age + Seed, data=Loblolly) > > # See the category names are all mangled up here > fit > > > Call: > lm(formula = height ~ age + Seed, data = Loblolly) > > Coefficients: > (Intercept) age Seed.L Seed.Q Seed.C > Seed^4 > -1.31240 2.59052 4.86941 0.87307 0.37894 -0.46853 > Seed^5 Seed^6 Seed^7 Seed^8 Seed^9 Seed^10 > 0.55237 0.39659 -0.06507 0.35074 -0.83442 0.42085 > Seed^11 Seed^12 Seed^13 > 0.53906 -0.29803 -0.77254 > > > > One possible solution I found is to rename the categorical variables > > seed.str <- paste("S", Loblolly$Seed, sep="") > seed.str <- factor(seed.str) > fit <- lm(height ~ age + seed.str, data=Loblolly) > fit > > > > Call: > lm(formula = height ~ age + seed.str, data = Loblolly) > > Coefficients: > (Intercept) age seed.strS303 seed.strS305 seed.strS307 > -0.4301 2.5905 0.8600 1.8683 -1.9183 > seed.strS309 seed.strS311 seed.strS315 seed.strS319 seed.strS321 > 0.5350 -1.5933 -0.8867 -0.3650 -2.0350 > seed.strS323 seed.strS325 seed.strS327 seed.strS329 seed.strS331 > 0.3067 -1.3233 -2.6400 -2.9333 -2.2267 > > > Now it is actually possible to see which one is which, but is kind of lame. > Can someone point me to a more elegant solution? Thank you so much. > > Saiwing Yeung > > ______________________________________________ > R-help@r-project.org 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. > -- ---------------------------------------------- My contact information: Tal Galili Phone number: 972-50-3373767 FaceBook: Tal Galili My Blogs: http://www.r-statistics.com/ http://www.talgalili.com http://www.biostatistics.co.il [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org 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.