w.r.t. the "affine regression" comment - you can reduce affine regression to linear regression by adding a constant feature whose value is 1 for every data poin

w.r.t. the "affine regression" comment - you can reduce affine regression to linear regression by adding a constant feature whose value is 1 for every data point, or by centering the data on its mean. So it's a fairly mild misnomer :) edit: of course, I agree that we should not say "linear function" when we mean "affine function" in general.