Probability density function in R
http://www.cyclismo.org/tutorial/R/probability.html
Chi square goodness-of-fit test in R
http://ww2.coastal.edu/kingw/statistics/R-tutorials/goodness.html
Chi square independence test in R
http://ww2.coastal.edu/kingw/statistics/R-tutorials/independ.html
ANOVA in R
http://personality-project.org/r/r.anova.html
