http://my.dreamwiz.com/lizard1/what_stat.html 
http://www.ttest.co.kr/
http://www.robertniles.com/stats/
http://directory.google.com/Top/Science/Math/Statistics/

http://www.wikipedia.org/wiki/Statistics

[[http://www.nmr.mgh.harvard.edu/Neural_Systems_Group/gary/python.html|collection of statistical functions in python]]