On Apr 16, 2013, at 20:12, Janh Anni <annijanh@gmail.com> wrote:
> Hello All,
>
> Would anyone be able to help me understand how R computes a
> quantile-quantile plot for comparing two data samples with unequal sample
> sizes? Normally, the procedure should be to rearrange the larger data
> sample into n equally-spaced parts using interpolation, where n is the
> sample size of the smaller sample, and then plot the matching data pairs.
I
> tried using different plotting position formulas for the interpolation but
> cannot reproduce what R is plotting. Thanks in advance.
If you type qqplot at the prompt you'll be given the code and can review it
for yourself. It's also available online for your viewing pleasure.
http://svn.r-project.org/R/trunk/src/library/stats/R/qqplot.R
It seems the key is the approx (linear interpolation) function, but you can work
out the details.
Michael
>
> Regards
> Janh
>
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>
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