[Rd] Documentation for sd (stats) + suggestion

PatrickT @nnoporc| @end|ng |rom gm@||@com
Wed Feb 20 18:49:38 CET 2019


Indeed. Thanks for your suggestions.

To elaborate briefly. The ``quantile`` function offers 9 types of methods.
The ``sd`` function only one. The ``mad`` function offers ways to tweak the
bias correction. The ``sd`` function doesn't.

Are there good reasons against adding features to ``sd``? after all it must
be one of the most popular stats out there.

Moreover the default ``sd`` function, which divides by n-1, is not well
founded like the variance is. It's still biased for repeated small
samples...

While it's easy to roll your own function, I don't think we can expect
beginners to write something like:

sdp = function(x) sqrt(sum((x-mean(x))^2)/length(x))


On Wed, Feb 20, 2019 at 9:00 AM Dario Strbenac <dstr7320 using uni.sydney.edu.au>
wrote:

> Good day,
>
> It is implemented by the CRAN package multicon. The function is named
> popsd. But it does seem like something R should provide without creating a
> package dependency.
>
> --------------------------------------
> Dario Strbenac
> University of Sydney
> Camperdown NSW 2050
> Australia
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> R-devel using r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
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