# A Good Enough Fit?

### Resources for this lesson:

You will use your Algebra II Journal on this page.

## Test and Confirm

To test the linear model, Andrew must examine both the residual plot and the correlation coefficient.  (Calculator instructions for calculating residuals and the correlation coefficient are available in the Calculator Resources section.)

Andrew realizes that to better assess the model, he will need to examine a residual plot.

A residual is the difference between the actual value in a data set and the estimated value from the line (or curve) of best fit.

## Algebra II Journal: Reflection 2

Use the line of best fit to calculate the estimated winning times and residual values in the following table in your Algebra II Journal. Submit your responses to your teacher.

Years since 2007

Winning time (minutes)

Estimated Winning Time (from Line of Best Fit)

Residual Value (Actual – Estimated)

0

16.33

16.8

1

16.77

16.756

2

17.5

3

16.77

4

16.35

5

16.42