Fitting to an Empirical Fuction

XYGrapher can optimize parameter values in an empirical fuction such that mean square error between measured and calculated values be minimum using the least square method. This is also called regression analysis.
First, XYGraper askes you which data series to be fitted. Select the target.
You can change the range of free variable (x), which is set at the same as the horizontal axis as default.
Unlike drawing function, free and bound variable must be xand y, respectively, and you cannot swap it.
After fitting, the curve is automatically drawn. You can change the attributes (style, width, and color) of the curve.
There are two categories of curve fitting: linear and nonlinear
You can switch reference axis for x , y, respectively.