Re: vertical or perpendicular offets?
- To: mathgroup at smc.vnet.net
- Subject: [mg67303] Re: [mg67295] vertical or perpendicular offets?
- From: Darren Glosemeyer <darreng at wolfram.com>
- Date: Sat, 17 Jun 2006 04:36:22 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
At 12:27 AM 6/16/2006 -0400, dantimatter wrote: >Hello all, > >Does anyone know what the Regress and NonlinearRegress functions in >Mathematica are minimizing? Is it the sum of the squares of the >perpendicular offsets or the vertical offsets? I would think that it >would be the vertical offsets, but then points that lie along a steep >part of a curve are weighted more heavily than points that lie along a >shallow part of the curve. > >Dan Regress and NonlinearRegress minimize the sum of squared errors (the vertical offsets). Weighted regression is often used to reduce the influence of extreme values on a fitted result. Weighted regression can be done by using the Weights option to Regress and NonlinearRegress. Darren Glosemeyer Wolfram Research