Brian...you might the short PowerPoint presentation on our website helpful. Keep hitting the spacebar and have your students describe what appears. While this is a one point simplification and you can argue it misses some of the fine points, it seems to help with the understanding for most students.

You will find it at

http://www.bbn-school.org/us/math/ap_stats/

under

Investigate-Explain/Downloadable PowerPoint Presentations/Understanding r-squared.

Make sure you get the PowerPoint file, not the Word file with the same title higher up on the page. You might find that exercise handy also though.

Al

-------------------------

Albert Coons

al_coons@bbns.org

Buckingham Browne & Nichols School

Gerry's Landing Road

Cambridge, MA 02138

(617) 800-2264

AP Statistics Web Site: www.bbn-school.org/us/math/ap_stats

On Sep 22, 2005, at 12:23 PM, Seitz, Brian M wrote:

I am using the YMM textbook, and my students are having trouble

understanding the interpretation of r^2. What is the best way to

explain this to them? For example, if r^2 = .6, what determines the

other .4 of the variation? Would it make sense to say that if r^2 for

wife's height and husband's height is .6, then the other .4 of the

variation is accounted for by other variables? Thanks, Brian Seitz

Northview HS Duluth, GA

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