[R] Looking for the name of a certain kind of quantile plot

[Carl Witthoft]

Thanks, Chuck.  That looks about right.

And I would have provided repro code, but I was forced to write it in 
Matlab on account of corporate rules, and haven't translated to R yet.


Carl Witthoft <carl at witthoft.com> writes:

 > Hi,
 > While playing with quantile-quantile plots, I wrote up some code which
 > plots something strangely different.  Here's the pseudocode:
 >
 > testhist <- hist(sample_data)
 > refhist <- hist(rnorm(n, mean=0,sd=1))  # for some large-ish n
 > cumtest <- cumsum(testhist)
 > cumref <- cumsum(refhist)
 >
 > plot(cumref,cumtest)


Sounds like a 'pp-plot'. See

       http://en.wikipedia.org/wiki/P-P_plot

Why not provide reproducible code?

Chuck

 >
 > This produces a straight line of slope 1 for a sample with the same
 > parameters as the reference sample, and produces S-curves for samples
 > with different sigmas.  A sample with nonzero mean looks almost
 > exponential (or logarithmic, depending on the sign of the mean).
 >
 > So my question is: is there a name for this sort of plot,  and is it
 > of any real use in statistical analysis?
 >
 > thanks.
 > Carl
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