Dear Alex, As explained in ?linearHypothesis, you can use matchCoefs() in the second argument:
linearHypothesis(reg, matchCoefs(reg, "year") , vcov=vcovHC(reg, "HC1")) In addition, you can set the argument white.adjust="hc1" as an alternative to using the vcov argument. Finally, in this case it would be simpler to just use Anova(), also with white.adjust="hc1". I hope this helps, John ------------------------------------------------ John Fox Sen. William McMaster Prof. of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada http://socserv.mcmaster.ca/jfox/ On Sun, 8 Jul 2012 18:45:22 -0700 (PDT) Waikato_alex <o...@waikato.ac.nz> wrote: > Hi everyone, > > I'm sure this is pretty basic but I couldn't find a clear example of how to > do this. I'm running a regression, say: > reg <- lm(Y ~ x1 + year) > where x1 is a continuous variable and year is a factor with various year > levels. Individually, each year factor variable is not significant, but I > have a suspicion they are jointly significant. I can't figure out how to run > a linearHypothesis test with a factor, i.e. > linearHypothesis(reg, ??? year=0 ??? , vcov=vcovHC(reg, , "HC1")) > > Would be very much appreciated. > > Many thanks, > > Alex > > -- > View this message in context: > http://r.789695.n4.nabble.com/linearHypothesis-and-factors-tp4635814.html > Sent from the R help mailing list archive at Nabble.com. > [[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. ______________________________________________ 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.