Re: vertical or perpendicular offets?
- To: mathgroup at smc.vnet.net
- Subject: [mg67304] Re: vertical or perpendicular offets?
- From: Bill Rowe <readnewsciv at earthlink.net>
- Date: Sat, 17 Jun 2006 04:36:25 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On 6/16/06 at 12:27 AM, dantimatter at gmail.com (dantimatter) wrote: >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. The assumed model in both of these packages is y = f(x) + error where the error term is assumed to come from a normal distribution. Standard regression packages (which include Regress and NonlinearRegress) minimize Sum[error^2, {1,n}] for the set of n data points. -- To reply via email subtract one hundred and four