In my first email,I wrote: summary(lm(extra~group))
Maybe the same as your "summary.lm" 2011/8/16 Jeff Newmiller <jdnew...@dcn.davis.ca.us> > ** Sorry, I missed the nature of the data. > > As to your original question, perhaps typing "summary.lm" at the R prompt > can enlighten you? > > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > --------------------------------------------------------------------------- > > Sent from my phone. Please excuse my brevity. > > Lao Meng <laomen...@gmail.com> wrote: >> >> The mean of group1 is 0.75,just the same as intercept. >> Acturally,R treated group1 as reference,so intercept is just group1. >> >> >> 2011/8/16 Jeff Newmiller <jdnew...@dcn.davis.ca.us> >> >>> Why would you assert that the mean is the same as the intercept? For data >>> clustered far from the y axis this seems clearly unlikely to be true. >>> >>> --------------------------------------------------------------------------- >>> Jeff Newmiller The ..... ..... Go Live... >>> DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... >>> Live: OO#.. Dead: OO#.. Playing >>> Research Engineer (Solar/Batteries O.O#. #.O#. with >>> /Software/Embedded Controllers) .OO#. .OO#. rocks...1k >>> --------------------------------------------------------------------------- >>> >>> Sent from my phone. Please excuse my brevity. >>> >>> Lao Meng <laomen...@gmail.com> wrote: >>> >>>> Hi all: >>>> I have a question about lm on t-test. >>>> >>>> data(sleep) >>>> >>>> I wanna perform t-test to test the difference between the 2 groups: >>>> >>>> I can use: >>>> t.test(extra~group) >>>> >>>> The t.test result shows that:t = -1.8608; mean1=0.75,mean2=2.33 >>>> >>>> >>>> But I still wanna use: >>>> summary(lm(extra~group)) >>>> >>>> Intercept=0.75,which is mean1,just the same as t.test. >>>> >>>> group2=1.58 means the difference of the 2 groups,so >>>> mean2=1.58+0.75=2.33,just the same as t.test. >>>> And some parameters of group2(t value,Pr) are the same as t.test,since >>>> group2 is the difference of the 2 groups. >>>> >>>> My question is: >>>> How the "t value" of Intercept(group1 acturally) is calculated? >>>> >>>> >>>> Thanks a lot. >>>> >>>> My best >>>> >>>> [[alternative HTML version deleted]] >>>> >>>> ------------------------------ >>>> >>>> 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. >>>> >>>> >> [[alternative HTML version deleted]] ______________________________________________ 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.
