Is this what you want? lm(y ~ fd + fd:y)
On 29/11/06, Andreas Goesele <[EMAIL PROTECTED]> wrote: > Hi, > > I would like to estimate something like y = a + b*d2*y + c*d3*y where > the dummies are created from some vector d with three (actually many > more) levels using factor(). But either there is included the variable > y or d1*y. How could I get rid of these? > > Example: > > x = c(1,2,3,4,5,6,7,8) > y = c(3,6,2,8,7,6,2,4) > d = c(1,1,1,2,3,2,3,3) > fd = factor(d) > > lm(x ~ fd*y) > gives: > > Coefficients: > (Intercept) fd2 fd3 y fd2:y fd3:y > 2.4231 9.5769 6.1822 -0.1154 -0.8846 -0.3320 > > lm(x ~ fd*y - y) > gives: > > Coefficients: > (Intercept) fd2 fd3 fd1:y fd2:y fd3:y > 2.4231 9.5769 6.1822 -0.1154 -1.0000 -0.4474 > > What I would like to get is: > > Coefficients: > (Intercept) fd2 fd3 fd2:y fd3:y > > Is there an easy way to achieve this? > > Maybe it's obvious how to do it, but I'm new to R did quite some > searching without finding the solution. > > Thanks a lot in advance! > > Andreas Goesele > > -- > Andreas Gösele > > ______________________________________________ > 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. > -- ================================= David Barron Said Business School University of Oxford Park End Street Oxford OX1 1HP ______________________________________________ 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.