Statistics Tip of the Week: Simple Non-linear Regression fits a curve to non-linear x,y data.

The "Simple" means that there is only one x variable. y = f(x). So the curve exists in two dimension and can be plotted on screen or sheet of paper. The "non-linear" means that, when we graph the data, it does not roughly follow a straight line, so we must look for an appropriate curve.

The following are probably the most common non-linear curves used:

Exponential and Logarithmic curves have rapid accelerations or decelerations
in the slope. Power curves have a more gradual change. Polynomial functions
can be used for more complex curves, which change direction, as shown in our Tip of the Week for May 17, 2017