SigmaPlot is described as 'Proprietary software package for scientific graphing and data analysis for Microsoft Windows.
The software can read multiple formats and perform mathematical transforms and statistical analyses' and is an app in the education & reference category. There are more than 10 alternatives to SigmaPlot for a variety of platforms, including Windows, Linux, Mac, Web-based and BSD apps. The best SigmaPlot alternative is MATLAB. It's not free, so if you're looking for a free alternative, you could try Matplotlib or LabPlot. Other great apps like SigmaPlot are OriginPro, SymPy, QtiPlot and NumeRe.