Statistical Tools - (Jan/08/2012 )

A very interresting site with several statistical tools and you can do it online (Clinical, Research, Calculators, Probabilities, Distributions, Frequency Data, Proportions, Ordinal Data, Correlation & Regression, t-Tests & Procedures, ANOVA, ANCOVA, Miscellanea)

http://faculty.vassa...assarStats.html

Thanks!
I find this one is good too:
http://udel.edu/~mcdonald/statintro.html