Recall from Lesson 5B that you can use the diagnostic feature on the graphing calculator to determine if a regression model fits a set of data accurately. Review this feature in Highlights.
  • Read the following carefully, and talk to your teacher if you have any questions.

The coefficient of determination, R2, measures how well a regression model represents a set of data. It is expressed as a value between zero and one. If R2 = 1, the regression curve passes through every point on the scatter plot. This indicates the regression curve models the data exactly. A value of zero indicates the regression curve is not an accurate model for the data.

Step 1: Open the CATALOG; press 2nd, 0 (zero), down arrow to scroll to DiagnosticOn.

Step 2: Turn on the diagnostic feature; press ENTER, ENTER.

In Example 3, you will see how the coefficient of determination is used to help determine if a model represents a given set of data accurately.