A fitted regression line on a graph represents of the mathematical regression equation for your data. Use fitted regression lines to illustrate the relationship between a predictor variable (x-scale) and a response variable (y-scale) and to evaluate whether the model fits your data.

A regression fit line can be drawn to fit a linear, quadratic, or cubic model.

You are studying the relationship between a particular machine setting and the amount of energy consumed. You suspect that this relationship has curvature, but you need to confirm and document the curvature. You produce the following plots. The quadratic model appears to fit the data better than a linear model.

Fitted regression lines can be added to graphs such as scatterplots and matrix plots.

- To add or edit a fitted regression line when you create a graph, in the dialog box for the graph you are creating, click Data View, and choose the Regression tab.
- To add a fitted regression line to an existing graph, right-click the graph and choose .