Thanks!
On Mon, Mar 25, 2013 at 6:25 PM, Joshua Wiley <jwiley.ps...@gmail.com>wrote: > Yep that's exactly right! :) > > On Mon, Mar 25, 2013 at 6:22 PM, Antonio P. Ramos > <ramos.grad.stud...@gmail.com> wrote: > > Just to clarify: I should include wealth - the categorical variable - as > a > > fixed effects *and* within the smooth using the argument "by". It that > > correct? thanks a bunch > > > > > > On Mon, Mar 25, 2013 at 6:18 PM, Joshua Wiley <jwiley.ps...@gmail.com> > > wrote: > >> > >> Hi Antonio, > >> > >> If wealth is a factor variable, you should include the main effect in > >> the model, as the smooths will be centered. > >> > >> Cheers, > >> > >> Josh > >> > >> > >> > >> On Mon, Mar 25, 2013 at 6:09 PM, Antonio P. Ramos > >> <ramos.grad.stud...@gmail.com> wrote: > >> > Hi all, > >> > > >> > I am not sure how to handle interactions with categorical predictors > in > >> > the > >> > GAM models. For example what is the different between these bellow two > >> > models. Tests are indicating that they are different but their > >> > predictions > >> > are essentially the same. > >> > > >> > Thanks a bunch, > >> > > >> >> gam.1 <- gam(mortality.under.2~ maternal_age_c+ I(maternal_age_c^2)+ > >> > + s(birth_year,by=wealth) + > >> > + + wealth + sex + > >> > + residence+ maternal_educ + birth_order, > >> > + ,data=rwanda2,family="binomial") > >> >> > >> >> gam.2 <- gam(mortality.under.2~ maternal_age_c+ I(maternal_age_c^2)+ > >> > + s(birth_year,by=wealth) + > >> > + + sex + > >> > + residence+ maternal_educ + birth_order, > >> > + ,data=rwanda2,family="binomial") > >> >> > >> >> anova(gam.1,gam.2,test="Chi") > >> > Analysis of Deviance Table > >> > > >> > Model 1: mortality.under.2 ~ maternal_age_c + I(maternal_age_c^2) + > >> > s(birth_year, > >> > by = wealth) + +wealth + sex + residence + maternal_educ + > >> > birth_order > >> > Model 2: mortality.under.2 ~ maternal_age_c + I(maternal_age_c^2) + > >> > s(birth_year, > >> > by = wealth) + +sex + residence + maternal_educ + birth_order > >> > Resid. Df Resid. Dev Df Deviance Pr(>Chi) > >> > 1 28986 24175 > >> > 2 28989 24196 -3.6952 -21.378 0.0001938 *** > >> > --- > >> > Signif. codes: 0 *** 0.001 ** 0.01 * 0.05 . 0.1 1 > >> >> str(rwanda2) > >> > 'data.frame': 29027 obs. of 18 variables: > >> > $ CASEID : Factor w/ 10718 levels " 1 5 2",..: > 289 > >> > 2243 7475 9982 6689 10137 7426 428 8415 10426 ... > >> > $ mortality.under.2 : int 0 1 0 0 0 0 0 0 1 0 ... > >> > $ maternal_age_disct: Factor w/ 3 levels "-25","+35","25-35": 1 1 1 > 1 1 > >> > 1 > >> > 3 1 3 1 ... > >> > $ maternal_age : int 18 21 21 23 21 22 26 18 27 21 ... > >> > $ time : int 3 3 3 3 3 3 3 3 3 3 ... > >> > $ child_mortality : num 0.232 0.232 0.232 0.232 0.232 ... > >> > $ democracy : Factor w/ 1 level "dictatorship": 1 1 1 1 1 1 > 1 1 > >> > 1 > >> > 1 ... > >> > $ wealth : Factor w/ 5 levels "Lowest quintile",..: 2 4 1 > 4 > >> > 5 1 > >> > 4 1 4 5 ... > >> > $ birth_year : int 1970 1970 1970 1970 1970 1970 1970 1970 > 1970 > >> > 1970 ... > >> > $ residence : Factor w/ 2 levels "Rural","Urban": 1 1 1 1 2 > 1 1 > >> > 1 > >> > 1 2 ... > >> > $ birth_order : int 1 2 2 5 1 1 3 1 2 2 ... > >> > $ maternal_educ : Factor w/ 4 levels "Higher","No education",..: > 3 > >> > 2 2 > >> > 3 4 2 3 2 2 2 ... > >> > $ sex : Factor w/ 2 levels "Female","Male": 1 1 2 2 1 > 1 2 > >> > 2 > >> > 2 2 ... > >> > $ quinquennium : Factor w/ 7 levels "00-5's","70-4",..: 2 2 2 2 > 2 > >> > 2 2 > >> > 2 2 2 ... > >> > $ time.1 : int 3 3 3 3 3 3 3 3 3 3 ... > >> > $ new_time : int 0 0 0 0 0 0 0 0 0 0 ... > >> > $ maternal_age_c : num -6.12 -3.12 -3.12 -1.12 -3.12 ... > >> > $ birth_year_c : num -14.8 -14.8 -14.8 -14.8 -14.8 ... > >> > > >> > [[alternative HTML version deleted]] > >> > > >> > > >> > ______________________________________________ > >> > 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. > >> > > >> > >> > >> > >> -- > >> Joshua Wiley > >> Ph.D. Student, Health Psychology > >> University of California, Los Angeles > >> http://joshuawiley.com/ > >> Senior Analyst - Elkhart Group Ltd. > >> http://elkhartgroup.com > > > > > > > > -- > Joshua Wiley > Ph.D. Student, Health Psychology > University of California, Los Angeles > http://joshuawiley.com/ > Senior Analyst - Elkhart Group Ltd. > http://elkhartgroup.com > [[alternative HTML version deleted]]
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