1/ if you type "statistics module python" in a google search engine, you'll find easily some modules with functions for statistics, so don't say you've searched the web !
2/ The list of all modules which come by default with the python distribution can be browsed in the documentation here http://docs.python.org/modindex.html . Other modules installed on your system should be in a folder called "site-packages" in your python library. Of course, you may have installed python modules elsewhere on your system. Run python like this
>>> import sys
>>> print sys.path
['', '/usr/lib/python2.5/site-packages/Pygments-0.8.1-py2.5.egg', '/home/eric/pymods', '/usr/lib/ooo-2.2/program', '/usr/lib/python25.zip', '/usr/lib/python2.5', '/usr/lib/python2.5/plat-linux2', '/usr/lib/python2.5/lib-tk', '/usr/lib/python2.5/lib-dynload', '/usr/lib/python2.5/site-packages', '/usr/lib/python2.5/site-packages/Numeric', '/usr/lib/python2.5/site-packages/PIL', '/usr/lib/python2.5/site-packages/gst-0.10', '/usr/lib/python2.5/site-packages/gtk-2.0', '/usr/lib/python2.5/site-packages/wx-2.6-gtk2-unicode'] The result is a list of folders where python looks for modules when you 'import' something. So you could look in these folders if you see some other modules installed (the list will be different on your system of course) !