Instructions

A "Begin" button will appear on the left when the applet is finished loading. This may take a minute or two depending on the speed of your internet connection and computer. Please be patient. If no begin button appears, it is probably because your browser does not support Java 1.1.

Starting the Applet and setting the conditions

Press the "Begin" button to start the applet in another window.

This applet lets you estimate the regression line and to guess the value of Pearson's correlation. Indicate your estimate of the regression line by drawing a line on the scatterplot. When you release the mouse button, the mean square error (MSE which is the average squared deviation of points from the line) is displayed. You can draw another line and see if you can lower the MSE. To see the best fitting line (by the criterion of least squares) select the "Draw regression line" option. To see the MSE for the best fitting line, select the "Show minimum MSE" option.

Five possible values of Pearson's correlation are listed. One of them is the correlation for the data displayed in the scatterplot. Guess which one it is. To see the correct value, click on the "Show r" button.

Click the "New Data" button to try again.

Credits

The simulations were developed as part of a grant from NSF to David Lane of Rice University. Partial support for this work was provided by the National Science Foundation's Division of Undergraduate Education through grant DUE 9751307. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.