Method of Least Squares for Fitting a Line
The applet below shows Example 11.1. Click on the "Hide/Display Error Squares" button so that the squared errors are displayed (yellow squares). Then drag the blue line to minimize the sum of the squares. The error meter on the left shows the current sum of squared errors. When you think you have found the best fit, click on the "Find Best Model" button to display the actual best model.
Another Example
The example below corresponds to Exercise 11.3.
Curvilinear Relationship
This applet illustrates that only the linear relationship is measured. In the graph below there is a strong curvilinear relationship between X and Y. What happens when you try to fit a sloped line to these data points?