On Sep 13, 2011, at 11:44 AM, David Winsemius wrote:


On Sep 13, 2011, at 9:43 AM, RCulloch wrote:

Dear John,

Thank you for that, and for explaining why the abline() command wont/dosen't work. The approach is based on reviewers comments that I am a tad sceptical about myself but yet curious enough to test their suggestion......I don't think it is very straightforward to explain; however, it involves using the
residuals of the lm() and plotting them against a covariate to assess
whether or not the deviation from the 1:1 relationship is in someway
influenced by the other covariate. I hope that shines a small amount of
light on this rather unorthodox approach?!

Plotting the residuals against a covariate is a standard way to assess the assumption that the residuals are distributed normally around each continuous regressor and have no non-linear relationship around each continuous regressor
Forgot to include homoschedasticity:

...and have a reasonably constant standard deviation across the range of the regressor...

. It is not to assess a "1:1 relationship", whatever that is. I think we would need to see a complete quotation of the reviewer's comments before deciding who is confused in this interchange.

--
David Winsemius, MD
West Hartford, CT

______________________________________________
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.

David Winsemius, MD
West Hartford, CT

______________________________________________
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.

Reply via email to