[R] "chi-square" | "chi-squared" | "chi squared" | "chi square" ?

Rolf Turner
2019-10-18T20:19:17Z

I have the vague impression that "chi-squared" is more common in
British
usage and "chi-square" more common in American usage.  I'm pretty
sure
that either is acceptable, although "chi-squared" sounds much better
to
my ear.

Of course within a given document (or collection of related documents)
consistency is mandatory.

cheers,

Rolf

On 19/10/19 1:51 AM, Martin Maechler 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
>       ?? - 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 ?2-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 [........]
>> [........]