| Breakpoint transforms
The breakpoint transforms option lets you use different transformation equations depending on whether data are less than or greater than a user-specified 'breakpoint' value. You enter the equations and the breakpoint in the following window:
After entering the breakpoint value, pick the type of equation for data below the breakpoint value, using the radio buttons at left. Then click the 'use this equation for data < breakpoint' button, and enter the a, b, and c values in the first set of edit fields at the bottom of the window. Then select the equation type for data equal to or greater than breakpoint, click the 'use this equation for data > breakpoint' button, and enter the a, b, and c values in the second set of edit fields. In this example, a 2-way polynomial will be applied to data < breakpoint, and an exponential equation will be applied to data > breakpoint. When all is correct, click the 'OK to transform' button to return to the main Transformations and Conversions window.