David wrote: > Linear: R2 0.90, B6 1100, B7 1250 > Quadratic: R2 0.99 B6 1400, B7 1900 > Exponential: R2 0.94 B6 1300, B7 1700 Can I just mention how incredibly exhilarating it is when someone whispers sweet equations in my ear? :-D Cindy -- who was with you up to "let's quarrel about the data"