Hi Michael,
You seem to have a quite recent mgcv if you are using qq.gam, so a help
file for version 1.3 is probably not going to be much help (gam.fit2 no
longer exists, for example).
By default qq.gam plots deviance residuals (see ?qq.gam). So the default
is standardization. When possible it then computes correct reference
quantiles for these, assuming that the model is correct.
See...
http://www.sciencedirect.com/science/article/pii/S0167947312000692
for details (or http://opus.bath.ac.uk/27091/1/qq_gam_resub.pdf)
best,
Simon
On 25/04/14 20:49, Folkes, Michael wrote:
Hello all,
I looking for confirmation of what I'm seeing. The qq plot in gam.check
and qq.gam is not standardizing the residuals.
The current help doesn't suggest they're standardized.
Somehow I found, online, a help for gam.check from version [Package
mgcv version 1.3-23 Index]:
"If the fit method is based on magic or gam.fit2 then there is no global
search and the problems with phantom local minima are much reduced. The
first plot in this case will simply be a normal QQ plot of the
standardized residuals."
This text is absent from the current help file.
If I'm correct, why is it that they aren't being standardized?
Much appreciated.
Michael
_______________________________________________________
Michael Folkes
Salmon Stock Assessment
Canadian Dept. of Fisheries & Oceans
Pacific Biological Station
3190 Hammond Bay Rd.
Nanaimo, B.C., Canada
V9T-6N7
Ph (250) 756-7264 Fax (250) 756-7053 michael.fol...@dfo-mpo.gc.ca
<mailto:michael.fol...@dfo-mpo.gc.ca>
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