[S] Testing for nonlinearity in GAM/GLM

Ottar N. Bjornstad (bjornsta@nceas.ucsb.edu)
Wed, 11 Mar 1998 23:36:50 +0100


Hi,

Can somebody please explain to me the test for the significanse of the nonlinear component that comes from summary.gam?

Why is the F-test rather than the chi-square test for difference in deviance between the linear and the nonlinear model?

I would like to test for the significance of nonlinearity in something like:
tmp_glm(Y~bs(X), family=quasi(variance="mu")

against

tmp2_glm(Y~X, family=quasi(variance="mu")

How is that test constructed?

Yours sincerely,
Ottar Bjørnstad
--------------------------------------------
Ottar N. Bjornstad http://www.uio.no/~ottarnb/
Until 2nd of April: NCEAS, 735 State St., Suite 300, Santa Barbara, CA 93101-3351
Tel. + 1 (805) 892 2511, Fax. + 1 (805) 892 2510

After that: Div. Zool., Dept. Biol., Univ. of Oslo, Box 1050 Blindern, N-0316 Oslo, Norway, Tel. + 47 22858370, Fax. + 47 22854605, mailto:ottarnb@bio.uio.no

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