Hi, Simon, I am using mgcv:gam and the version number is mgcv_1.5-2. I also exchanged the order of two models in anova, but this also did not help. >From the differences in DF(0.77246) and deviance (-0.02), these two models seem to be not significantly different. Isn't it? Thank you anyway!
Simon Wood-4 wrote: > > The simpler model has the lower deviance (marginally), so there is nothing > to > test here. This can happen with maximum penalized likelihood estimators, > even > though the models are nested (especially if the smoothing parameters are > selected automatically). Are you using gam:gam or mgcv:gam (and which > version > numbers)? > > best, > Simon > > On Tuesday 28 April 2009 12:38, willow1980 wrote: >> Hello, everybody, >> There is the first time for me to post a question, because I really >> cannot >> find answer from books, websites or my colleagues. Thank you in advance >> for >> your help! >> I am running likelihood ratio test to find if the simpler model is not >> significant from more complicated model. However, when I run LRT to >> compare >> them, the test did not return F value and p-value for me. What's the >> reason? How can I get such important information? >> >> #################################################### >> Analysis of Deviance Table >> >> Model 1: sum_surv15 ~ s(FLBS) + s(byear) + s(FLBS, byear) >> Model 2: sum_surv15 ~ s(FLBS) + SES + s(byear) + s(FLBS, byear) >> Resid. Df Resid. Dev Df Deviance F Pr(>F) >> 1 1202.21094 601.27 >> 2 1201.43848 601.29 0.77246 -0.02 >> #################################################### >> Thank you very much! >> >> Jianghua Liu, University of Sheffield > > -- >> Simon Wood, Mathematical Sciences, University of Bath, Bath, BA2 7AY UK >> +44 1225 386603 www.maths.bath.ac.uk/~sw283 > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > > -- View this message in context: http://www.nabble.com/Why-there-is-no-p-value-from-likelihood-ratio-test-using-anova-in-GAM-model-fitting--tp23275224p23278595.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
