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Date:         Tue, 20 Apr 2004 04:18:45 -0400
Reply-To:     Subscribe Sas-L Anonymous <susi_i@HOTMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Subscribe Sas-L Anonymous <susi_i@HOTMAIL.COM>
Subject:      Re: Orthogonal regression?
Comments: To: "(GVSUG) Paige Miller" <paige.miller@KODAK.COM>


Just read the posts here about orthogonal regression....

I need to perform this in order to obtain the slope for use in a device calibration study.

It has been suggested that I use PROC CALLIS, but I don't really understand the methodology. The PROC PRINCOMP code and output looks easier to understand, however I don't know how to obtain the slope from this, and don't have access to the book mentioned by Paige in the previous post.

Can anyone help?

Many thanks, Susi

On Thu, 5 Jun 2003 08:34:04 -0400, Paige Miller <paige.miller@KODAK.COM> wrote:

>simian wrote: >> Hello all, >> >> I am trying to figure out how to do an orthogonal regression with two >> variables in base SAS. The goal is to identify which sample points >> fall outside of certain standard deviation bands (say, +/- 1 SD) as >> measured by the perpendicular distance to a regression line. My >> variables X and Y are in the same units. >> >> I understand that PROC ORTHOREG is not designed to do this. On my >> data set, it produces essentially the same slope and intercept as PROC >> REG. > >The orthogonal regression line can be determined from the first >principal component, therefore you will need PROC PRINCOMP and some >additional calcs that you will have to write yourself. The details can >be found in Jackson, J. E. (1991) "A User's Guide to Principal >Components", John Wiley and Sons, NY. See Chapter 15. Please note that >formula 15.2.4 is incorrect due to typographical error. > >-- >Paige Miller > > > >"It's nothing until I call it!" -- Bill Klem, NL Umpire >"When you get the choice to sit it out or dance, I hope you dance" -- >Lee Ann Womack

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