two options are to use an offset term or the linear.hypothesis() function from package car, e.g.,
y <- rnorm(100, 2 - 1 * (x <- runif(100, -3, 3)), 3) ############ fit0 <- lm(y ~ 1 + offset(-x)) fit1 <- lm(y ~ x) anova(fit0, fit1) library(car) linear.hypothesis(fit1, c("x = -1")) I hope it helps. Best, Dimitris ---- Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm Quoting Indermaur Lukas <[EMAIL PROTECTED]>: > Hello > Instead of testing against 0 i would like to test regression slopes > against -1. Any idea if there's an R script (package?) available. > > Thanks for any hint. > Cheers > Lukas > > > > > °°° > Lukas Indermaur, PhD student > eawag / Swiss Federal Institute of Aquatic Science and Technology > ECO - Department of Aquatic Ecology > Überlandstrasse 133 > CH-8600 Dübendorf > Switzerland > > Phone: +41 (0) 71 220 38 25 > Fax : +41 (0) 44 823 53 15 > Email: [EMAIL PROTECTED] > www.lukasindermaur.ch > > ______________________________________________ > 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. > > Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ______________________________________________ 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.