http://lab.sdm.keio.ac.jp/ogi/shibaura/ed6-1108.pdf
https://kusuri-jouhou.com/statistics/fkentei.html
https://bellcurve.jp/statistics/course/9934.html
https://www.trunktools.jp/services/analysis/f.html
https://bdastyle.net/tools/test/equality_of_2variances.html
https://qiita.com/neuman71/items/8fd49be7ae572dbdede5
http://www.aoni.waseda.jp/abek/document/t-test.html