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.

Reply via email to