DataFit

DataFit is a tool for performing nonlinear regression (curve fitting) and data plotting with up to 20 independent variables. You can define your own regression models, or choose from more than 350 predefined 2D/3D models. Results include 2D and 3D plots and a variety of fitting parameters. You can also export code in BASIC or C to use a model in a user-written program. This program includes the addition of 3D color-contour plotting capability and new plot text formatting features, such as superscripting and subscripting. It also provides the ability to create a spreadsheet of evaluated regression models through user-specified intervals, providing interpolated and extrapolated values of the equation. New features in version 9.0 include Intuitive Graphical Interface, non-graphical execution, online help and "tool-tip" text .