pro Fit is a Macintosh (Mac OS) application for data/function analysis,plotting, and curve fitting. It is used by scientists and engineers toanalyze their measurements and the mathematical models they use todescribe them. Scientists or students can define any mathematical function and use itto model their data, finding by linear or nonlinear curve fitting thefunction parameters that best describe their observations. Moreover,they can use a number of tools for the mathematical and statisticalanalysis of functions and data sets, and they can produce estheticallypleasing graphical representations for their scientific reports.