[Python-ideas] Adding quantile to the statistics module

[Stephen J. Turnbull]

Steven D'Aprano writes:

 > Indeed. I've been considering quantiles and quartiles for a long time, 
 > and I've found at least ten different definitions for quantiles and 
 > sixteen for quartiles.

My take is "don't let the perfect be the enemy of the good."
Quantiles are used a lot for "government work".  Pick a definition
that's good enough for that.

Pick one that is commonly used and has nice invariance properties if
any are applicable (e.g., quartile1(list) == quartile3(reversed(list),
although I'm not even sure that is appropriate!), document it
carefully, and give (some) examples of the edge cases that affect
comparability of the statistics module's computation to alternative
formulae.

I'd like to see your list written up.  To my mind, it would be of
enough general interest that you could probably publish the results of
your research in a political science or maybe psychology journal, or a
statistics journal oriented to practitioners and/or educators[1].  I'm
not suggesting you should do the work involved in actually submitting
unless there's benefit to you in it, I'm just saying I think it's that
interesting.

Regards,

Steve


Footnotes: 
[1]  I'd find it useful in talking to my students about trusting
computers, for one thing.