On Wed, 3 Aug 2005, Simon Blomberg wrote: > This is two tests: Whether the slope != 1 and whether the intercept != 0.
Neither model given has an intercept .... > To do this, include an offset in your model: > > fit <- lm(y ~ x + offset(x), data=dat) but no intercept, so use summary(lm(y ~ 0 + x + offset(1.05*x), data=dat)) and look if the coefficient of x is significantly different from zero. E.g. x <- 1:10 set.seed(1) y <- 1.05*x + rnorm(10) summary(lm(y ~ 0 + x + offset(1.05*x))) Coefficients: Estimate Std. Error t value Pr(>|t|) x 0.03061 0.03910 0.783 0.454 is not. > > HTH, > > Simon. > > > At 03:44 PM 3/08/2005, [EMAIL PROTECTED] wrote: >> >> I am wondering how to test whether a simple linear regression model >> (e.g. y=1.05x) is significantly different from a 1 to 1 line (i.e. y=x). -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
