分散分析(ANOVA)
http://www.personality-project.org/R/r.anova.html
http://www.ats.ucla.edu/stat/r/seminars/repeated_measures/repeated_measures.htm
http://zoonek2.free.fr/UNIX/48_R/13.html
http://www.psych.upenn.edu/~baron/rpsych/rpsych.html#SECTION00079000000000000000
日本語
http://mat.isc.chubu.ac.jp/R/tech.html
http://mjin.doshisha.ac.jp/R/12.pdf