Message-ID: <89b6b8c90911020842p11882827q6927be50aec5129@mail.gmail.com>
Date: 2009-11-02T16:42:05Z
From: Yihui Xie
Subject: qqplot
In-Reply-To: <333058.51369.qm@web62002.mail.re1.yahoo.com>
abline(0,1) is somewhere in the upper-left corner which you are unable
to see. At least the first distribution seems to have a larger mean
than the second one (i.e. they are not the same distribution).
Regards,
Yihui
--
Yihui Xie <xieyihui at gmail.com>
Phone: 515-294-6609 Web: http://yihui.name
Department of Statistics, Iowa State University
3211 Snedecor Hall, Ames, IA
On Mon, Nov 2, 2009 at 10:33 AM, carol white <wht_crl at yahoo.com> wrote:
> if I have the two following matrices, abline(0,1) doesn't go through. QQplot is attached.
>
> ? ? ? ? ? ?[,1] ? ? [,2] ? ? [,3] ? ? [,4] ? ? [,5]
> ?2.149644 1.992864 3.346375 2.793511 3.428230
> ?1.100762 2.152981 2.735401 2.175185 3.323058
> 1.212406 2.131813 2.672598 2.389996 3.242490
> 1.183770 1.908633 2.661237 2.590545 2.906059
> ?1.665190 1.778923 2.636062 2.475619 4.013407
>
>
> ? ?0.601 ? 0.083 ? 0.520 ? ?0.920 ?-0.007
> ? -0.778 ? 0.427 ?-0.605 ? -0.066 ?-0.283
> ?-0.599 ? 0.348 ?-0.693 ? ?0.284 ?-0.436
> ? -0.519 ? 0.081 ?-0.590 ? ?0.678 ?-1.095
> ? ?0.009 ?-0.253 ?-0.940 ? ?0.526 ? 1.623
>
>
> --- On Mon, 11/2/09, David Winsemius <dwinsemius at comcast.net> wrote:
>
>> From: David Winsemius <dwinsemius at comcast.net>
>> Subject: Re: [R] qqplot
>> To: "carol white" <wht_crl at yahoo.com>
>> Cc: r-help at stat.math.ethz.ch
>> Date: Monday, November 2, 2009, 8:17 AM
>>
>> On Nov 2, 2009, at 10:40 AM, carol white wrote:
>>
>> > Hi,
>> > We could use qqplot to see how two distributions are
>> different from each other. To show better how they are
>> different (departs from the straight line), how is it
>> possible to plot the straight line that goes through them? I
>> am looking for some thing like qqline for qqnorm. I thought
>> of abline but how to determine the slope and intercept?
>>
>> I always assumed that the intercept was zero and the slope
>> = unity.
>>
>> ?y <- rt(200, df = 5)
>> ?qqnorm(y); qqline(y, col = 2)
>> ?qqplot(y, rt(300, df = 5))
>> ?abline(0, 1, col="red")
>>
>> I am open to education if that assumption is too
>> simplistic, but you have not offered anything in the way of
>> a counter-example.
>>
>> >
>> ==
>>
>> David Winsemius, MD
>> Heritage Laboratories
>> West Hartford, CT
>>
>>
>
>
>
> ______________________________________________
> R-help at 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.
>
>