Re: regress versus fit - force through zero/force constant term to zero
- To: mathgroup at smc.vnet.net
- Subject: [mg61521] Re: regress versus fit - force through zero/force constant term to zero
- From: dh <dh at metrohm.ch>
- Date: Fri, 21 Oct 2005 00:38:04 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi Chris, I stumbeled myself over this behaviour of Regress. Here is an excerpt from the Help of Regress: Two of the options of Regress influence the method of calculation. IncludeConstant has a default setting True, which causes a constant term to be added to the model even if it is not specified in the basis functions. To fit a model without this constant term, specify IncludeConstant -> False and do not include a constant in the basis functions. Daniel Chris Chiasson wrote: > Hi MathGroup, > > If I have: > <<Statistics`LinearRegression` > FAASCalPts={{1,0.032},{2,0.067},{5,0.183}} > FAASCalFit=Fit[FAASCalPts,{cCaPos},cCaPos] > FAASCalRegression= > Regress[FAASCalPts,{cCaPos},cCaPos, > RegressionReport\[Rule]{SummaryReport,BestFit}] > > I expect the answer from Fit, but not the one from Regress. Regress > seems to be ignoring the fact that I only want the first order (and > not the zero/constant order) term. > > How do I obtain fit diagnostics if I am forcing a 0 for the constant order? > > Thank you, > -- > Chris Chiasson > http://chrischiasson.com/contact/chris_chiasson >