MGCV: Degrees of freedom of smooth terms
Dear all, This is just a quick question regarding degrees of freedom in GAM models fit by MGCV (using select=T): Can I roughly interpret them as: 1 df: linear effect of x on y 2 df: approximately quadratic of x on y 3 df: approximately cubic effect of x on y? 1 df for a spatial term s(x,y): bilinear effect (?) or how would I call this? And what does "ref.df" in the summary output mean; is this the unpenalized degrees of freedom for each term? Thank you very much for answering! Best wishes, Christoph
PD Dr Christoph Scherber Georg-August University Goettingen Department of Crop Science Agroecology Grisebachstrasse 6 D-37077 Goettingen Germany phone 0049 (0)551 39 8807 fax 0049 (0)551 39 8806 http://www.gwdg.de/~cscherb1