I proposed adding a statistics module to the standard library some time ago, and received some encouragement:

http://mail.python.org/pipermail/python-ideas/2011-September/011524.html

Real life intervened, plus a bad case of over-engineering, but over the last few weeks I have culled my earlier (private) attempt down to manageable size. I would like to propose the attached module for the standard library.

I also have a set of unit-tests for this module. At the moment it covers about 30-40% of the functions in the module, but I should be able to supply unit tests for the remaining functions over the next few days.