Regression slope confidence interval
?confint
Thank you to all of you. As far as I see this is not mentioned on the lm help page (though I presumably don't have the recent version), which I would suggest... Best, Christian
On Thu, 29 Sep 2005, Chuck Cleland wrote:
?confint For example:
> ctl <- c(4.17,5.58,5.18,6.11,4.50,4.61,5.17,4.53,5.33,5.14)
> trt <- c(4.81,4.17,4.41,3.59,5.87,3.83,6.03,4.89,4.32,4.69)
> group <- gl(2,10,20, labels=c("Ctl","Trt"))
> weight <- c(ctl, trt)
> lm(weight ~ group)
Call:
lm(formula = weight ~ group)
Coefficients:
(Intercept) groupTrt
5.032 -0.371
> confint(lm(weight ~ group))
2.5 % 97.5 % (Intercept) 4.569340 5.4946602 groupTrt -1.025300 0.2833003 Christian Hennig wrote:
Hi list, is there any direct way to obtain confidence intervals for the regression slope from lm, predict.lm or the like? (If not, is there any reason? This is also missing in some other statistics softwares, and I thought this would be quite a standard application.) I know that it's easy to implement but it's for explanation to people who faint if they have to do their own programming... Christian *** --- *** Christian Hennig University College London, Department of Statistical Science Gower St., London WC1E 6BT, phone +44 207 679 1698 chrish at stats.ucl.ac.uk, www.homepages.ucl.ac.uk/~ucakche
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*** --- *** Christian Hennig University College London, Department of Statistical Science Gower St., London WC1E 6BT, phone +44 207 679 1698 chrish at stats.ucl.ac.uk, www.homepages.ucl.ac.uk/~ucakche