On 1/8/2008 2:48 PM, Knut Krueger wrote: > Hi to all, > Is there a possibility to choose which value is used for the intercept > or does in not make any sense? > f.e I would like to use outcome2 for the intercept > > ## Dobson (1990) Page 93: Randomized Controlled Trial : > counts <- c(18,17,15,20,10,20,25,13,12) > outcome <- gl(3,1,9) > treatment <- gl(3,3) > print(d.AD <- data.frame(treatment, outcome, counts)) > glm.D93 <- glm(counts ~ outcome + treatment, family=poisson()) > summary(glm.D93 > > > Coefficients: > Estimate Std. Error z value Pr(>|z|) > (Intercept) 3.045e+00 1.709e-01 17.815 <2e-16 *** > outcome2 -4.543e-01 2.022e-01 -2.247 0.0246 * > outcome3 -2.930e-01 1.927e-01 -1.520 0.1285 > treatment2 8.717e-16 2.000e-01 4.36e-15 1.0000 > treatment3 4.557e-16 2.000e-01 2.28e-15 1.0000 > > > Regards Knut
Here is one way: outcome <- relevel(outcome, ref="2") ?relevel > ______________________________________________ > 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. -- Chuck Cleland, Ph.D. NDRI, Inc. 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894 ______________________________________________ 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.