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
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David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
