ref.df in mgcv gam
Thank you, Dr. Wood, that is very helpful. Best, Susan
On Wed, Mar 27, 2019 at 12:10 PM Simon Wood <simon.wood at bath.edu> wrote:
These are a bit of a throwback really, and are not very useful - they are reference degrees of freedom used in computing test statistic and the p-values, but since the null distributions are non-standard the reference DoF is not very interpretable. best, Simon On 27/03/2019 13:58, Susan Elias wrote:
Hello Group. Regarding degrees of freedom in GAM models fit by mgcv, I do understand
the
estimated df, but what does "ref.df" in the summary output mean? I didn't see an explanation in Wood (2017) or find it in the function code. The answer may be on page 222 of Wood SN. On p-values for smooth components of an extended generalized additive model. Biometrika 2013;100(1):221-228 or thereafter, but I am not a statistician. I could use help
understanding
what the reference degrees of freedom are. Thank you, Susan
-- Simon Wood, School of Mathematics, University of Bristol, BS8 1TW UK https://people.maths.bris.ac.uk/~sw15190/
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Susan Elias PhD Candidate, School of Earth and Climate Sciences, University of Maine Research Associate, Vector-borne Disease Lab, Maine Medical Center Research Institute 207-756-2761 [[alternative HTML version deleted]]