Correlation and Regression

Authors:  Bob Hall, Arlen Strader, and Jonathan Hall, Texas A&M University

On this page, students can view and compare scatterplots for different magnitudes of correlation.  In addition, there is information about problems affecting interpretation of correlation coefficients and links to step-by-step presentations for how to compute correlation coefficients as well as some basic information about correlation.

The Correlation/Regression applet offers a series of linked workspaces in which data can be entered directly into a grided scatterplot complete with user controlled scaling of the X and Y axes.  Points placed on the scatterplot are automatically entered into a deviation-score summary table (separate applet) and values from the summary table are passed to a formulas applet that displays computations for means, standard deviations, covariance, correlation, slope, and intercept values.  Students can observe how values are computed and can request more detailed information about the interpretation and computation of those values (i.e., mean, standard deviation, etc.).  Any changes made in the summary table are reflected in the dynamic updating of the scatterplot and formula applets.  Data can be imported or exported into the summary table and the scatterplot can be printed.

Correlation Interpretation