The following are Web addresses for Java Applets for working with the Least Squares Regression line, correlation coeffiecients, and minimizing the sums of squares.
Web site for Least Squares Regression Line. It shows geometrically the minimization of the sum of the squares of the residuals of a line.


Key curriculum statistics applets 

Shows the effect of outliers and influential points. 

http://www.stat.Berkeley.EDU/users/stark/Java/Correlation.html 
Shows LSRL, correlation coefficient and influential points. 