I would try to construct the confidence intervals and compare them to the value that you want > x <- rnorm(20) > y <- 2*x + rnorm(20) > summary( m1 <- lm(y~x) )
<snip> Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 0.1418 0.1294 1.095 0.288 x 2.2058 0.1289 17.108 1.4e-12 *** <snip> That says that the slope estimate is 2.2058 with standard error of 0.1289. So the approximate 99% CI is 2.2058 +/- 3*0.1289 = (1.819, 2.593) which is clearly greater than 1. > summary(m1)[[4]][2,1] + 3* summary(m1)[[4]][2,2] [1] 2.592629 > summary(m1)[[4]][2,1] - 3* summary(m1)[[4]][2,2] [1] 1.819026 For your next question, you simply compare the CI of one slope to another and see if they overlap. There is probably a way to construct proper significance testing to get p-values and such. You can try reading MASS4 or hopefully someone in the list might provide with a neater answer. On Tue, 2004-07-20 at 17:02, Avril Coghlan wrote: > Hello, > > I'm a newcomer to R so please > forgive me if this is a silly question. > > It's that I have a linear regression: > fm <- lm (x ~ y) > and I want to test whether the > slope of the regression is significantly > less than 1. How can I do this in R? > > I'm also interested in comparing the > slopes of two regressions: > fm1 <- lm (x ~ y) > fm2 <- lm (a ~ b) > and asking if the slope of fm1 is > less than the slope of fm2. Is this > easy to do in R? > > > I will be very grateful for any help. > > regards, > Avril Coghlan > (University College Dublin, Ireland) > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html