SigmaStat is a statistical software package, which was originally developed by Jandel Scientific Software in the 1980s. As of October 1996, Systat Software is now based in San Jose, California. SigmaStat users have the ability to compare effects among groups. This includes before and after or repeated measure studies. The users can also conduct survival analysis, analyze rates and proportions, perform regression and correlation analysis and calculate power and sample size.