1. Understanding r-squared: A single point simplification
Al Coons
Buckingham Browne & Nichols School
Cambridge, MA

2. y
Error w.r.t. mean model
Error eliminated by y-hat model
Proportion of error eliminated by Y-hat model
Error eliminated by y-hat model =
Error w.r.t. mean model
r2 = proportion of variability accounted for by the given model (w.r.t the mean model).

3. y ~ Error w.r.t. mean model Error eliminated by y-hat model
Proportion of error eliminated by Y-hat model
Error eliminated by y-hat model =
Error w.r.t. mean model = ~