[R] [EXTERNAL] Re: "chi-square" | "chi-squared" | "chi squared" | "chi square" ?

Mon Oct 21 13:09:37 CEST 2019

Pearson's original paper uses both \chi and \chi^2 frequently but
never spells out how to pronounce the latter.
Try another question: when talking about \sigma^2 do you say
"sigma-square" (which sounds rather odd) or "sigma-squared" (which
sounds more natural)?  If you say sigma-square, say chi-square.  If
you say sigma-squared, say chi-squared.
For what it's worth, the multu=i-volume "Encyclopedia of Statistical
Sciences", 2nd edition, uses both variants.
And so does Kendal & Stuart, volume 2, 1961, although "-squared" seems
to predominate.

On Sat, 19 Oct 2019 at 11:27, Dalthorp, Daniel via R-help
<r-help using r-project.org> wrote:
>
> oh my...
>
> I'd like to see the statistics on it before jumping to a conclusion that
> the American preference is "chi-square" and the British preference is
> "chi-squared". I don't see that at all.
>
> ------
> In keeping with the pronunciation of x^2 and 3^2, maybe "chi-squared" makes
> the most sense,.
>
> The "chi-square"? Because the iterated dentals in "chi-squared
> distribution" and "chi-squared test" are a little cumbersome to pronounce,
> an even slightly lazy pronunciation would sound like "chi-square
> distribution" and "chi-square test". There's no need to write it that way
> though.
>
> -Dan
>
>
>
> On Fri, Oct 18, 2019 at 2:28 PM Richard M. Heiberger <rmh using temple.edu> wrote:
>
> > What a delightful question.  Bill Cochran discussed this in class
> > one day about 50 years ago.  He said the British usage (which I think
> > he said was chi-squared,
> > as is consistent with the other memories in this thread)
> > is what he learned and previously used.  But he had been in the US for
> > so long that he was now using
> > the American preference (chi-square).
> >
> > Rich
> >
> > On Fri, Oct 18, 2019 at 8:51 AM Martin Maechler
> > <maechler using stat.math.ethz.ch> wrote:
> > >
> > > As it's Friday ..
> > >
> > > and I also really want to clean up help files and similar R documents,
> > > both in R's own sources and in my new 'DPQ' CRAN package :
> > >
> > > As a trained mathematician, I'm uneasy if a thing has
> > > several easily confusable names, .. but as somewhat
> > > humanistically educated person, I know that natural languages,
> > > English in this case, are much more flexible than computer
> > > languages or math...
> > >
> > > Anyway, back to the question(s) .. which I had asked myself a
> > > couple of months ago, and already remained slightly undecided:
> > >
> > > The 0-th (meta-)question of course is
> > >
> > >   0. Is it worth using only one written form for the
> > >      χ² - distribution, e.g. "everywhere" in R?
> > >
> > > The answer is not obvious, as already the first few words of the
> > > (English) Wikipedia clearly convey:
> > >
> > > The URL is  https://en.wikipedia.org/wiki/Chi-squared_distribution
> > > and the main title therefore also
> > >     "Chi-squared distribution"
> > >
> > > Then it reads
> > >
> > > > This article is about the mathematics of the chi-squared
> > > > distribution. For its uses in statistics, see chi-squared
> > > > test. For the music [...]
> > >
> > > > In probability theory and statistics, the chi-square
> > > > distribution (also chi-squared or χ2-distribution) with k
> > > > degrees of freedom is the distribution of a sum of the squares
> > > > of k independent standard normal random variables.
> > >
> > > > The chi-square distribution is a special case of the gamma
> > > > distribution and is one of the most widely used probability
> > > > distributions in inferential statistics, notably in hypothesis
> > > > testing [........]
> > > > [........]
> > >
> > > So, in title and 1st paragraph its "chi-squared", but then
> > > everywhere(?) the text used "chi-square".
> > >
> > > Undoubtedly, Wilson & Hilferty (1931) has been an important
> > > paper and they use "Chi-square" in the title;
> > > also  Johnson, Kotz & Balakrishnan (1995)
> > > see R's help page ?pchisq use  "Chi-square" in the title of
> > > chapter 18 and then, diplomatically for chapter 29,
> > >  "Noncentral χ²-Distributions" as title.
> > >
> > > So it seems, that historically and using prestigious sources,
> > > "chi-square" to dominate (notably if we do not count "χ²" as an
> > > alternative).
> > >
> > > Things look a bit different when I study R's sources; on one
> > > hand, I find all 4 forms (s.Subject); then in the "R source
> > > history", I see
> > >
> > >   $ svn log -c11342
> > >
> >  ------------------------------------------------------------------------
> > >   r11342 | <....> | 2000-11-14 ...
> > >
> > >   Use `chi-squared'.
> > >
> >  ------------------------------------------------------------------------
> > >
> > > which changed 16 (if I counted correctly) cases of 'chi-square' to
> > 'chi-squared'.
> > >
> > > I have not found any R-core internal (or public) reasoning about
> > > that change, but had kept it in mind and often worked along that "goal".
> > >
> > > As a consequence, "statistically" speaking, much of R's own use has been
> > > standardized to use "chi-squared"; but as I mentioned, I still
> > > find all  4  variants even in "R base" package help files
> > > (which of course I now could quite quickly change  (using Emacs M-x
> > grep, plus a script);
> > > but
> > >
> > > ... "as it is Friday" ... I'm interested to hear what others
> > > think, notably if you are native English (or "American" ;-)
> > > speaking and/or have some extra good knowledge on such
> > > matters...
> > >
> > > Martin Maechler
> > > ETH Zurich
> > >
> > > ______________________________________________
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> >
>
>
> --
> Dan Dalthorp, PhD
> USGS Forest and Rangeland Ecosystem Science Center
> Forest Sciences Lab, Rm 311
> 3200 SW Jefferson Way
> Corvallis, OR 97331
> ph: 541-750-0953
> ddalthorp using usgs.gov
>
>         [[alternative HTML version deleted]]
>
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