Thanks. I found the code in the link you gave me very helpful.
But, I just have few questions regarding the code.
It seems to me that in (from wikipdeia)Deming regression, it assumes that
the ratios of the variances of two measurement errors are constant for all
pairs of (x_i, y_i). However, if the ratios are not constant, (i.e. the
variances of measurement are heterogeneous) , is it still appropriate to use
Deming regression ?

Thanks for any suggestions!

Carrie--



2010/8/7 Christos Argyropoulos <argchris@hotmail.com>

>
> I believe there was a fairly recent exchange (within the last 6 months)
> about linear measurement error models/error-in-variable models/Deming
> regression/total least squares/orthogonal regression.  Terry Therneau
> provided code for an R function that can estimate such models:
>
> http://www.mail-archive.com/r-help@r-project.org/msg85070.html
>
> If your knowledge of Fortran is up to the task, there is a Netlib package
> called ODRpack that can fit such models. Kind of surprising that no one has
> not written a R wrapper for this library (yet).
>
> Christos
>
> ----------------------------------------
> > Date: Sat, 7 Aug 2010 11:21:01 -0400
> > From: carrieandstat@gmail.com
> > To: R-help@r-project.org
> > Subject: [R] package for measurement error models
> >
> > Hi,all,
> >
> > I posted this question couple of days again, but haven't gotten any
> answers
> > back. I would like to post it again, and if you have any ideas, please
> let
> > me know. Any helps and suggestions are very much appreciated.
> >
> > The problem is about linear regression with both y and x have
> measurement,
> > and the variance of errors are heterogeneous. The estimated regression
> > coefficient and its variance are of interest. Is any R package doing this
> > task ?
> >
> > Thank you
> >
> > Carrie--
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
>

	[[alternative HTML version deleted]]

