Statistics - Calculating Standard Deviation

I'd like to be able to calculate the standard deviation of a set of
numbers - much as sun() does.
I've had a look at various websites, extensions etc, and cannot find
anything.
Does anyone know if such functionality is available (and if so - where I
can get it from:)) or should I write my own?


Thx.
Hugh Dixon

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list