Use the mouse to put points in the blue area. After each point, the correlation coefficient and the regression equation will be calculated. To remove points, select the "Erase point" option, then click on the point you want removed. "Clear plot" will remove all the points; "Residuals" will pop up a scatter plot of X versus the residuals, as well as a histogram of the residuals. To add random points to the plot, press "Random points," after changing the number and correlation for the new points if you wish.
