För att jämföra medelvärden Another nice tool for a two-group study http://www.stat.ubc.ca/~rollin/stats/ssize/n2.html http://www.stat.ubc.ca/~rollin/stats/ssize/n2.html Afkastareiknir Rollins Brants http://www.stat.ubc.ca/~rollin/stats/ssize/n2.html Power Analysis Tool Sample size/power for two independent means http://www.stat.ubc.ca/~rollin/stats/ssize/n2.html