Hi, I just found out type III ANOVA won't give me model comparison result, am I not suppose to do model comparison with type III ANOVA? Say we have two models m1=lm(data~factor1+factor2,data=table) m2=lm(data~factor1*factor2,data=table) Type I ANOVA comparison anv1=anova(m1,m2) Type III ANOVA Comparison, from car package anv2=Anova(m1,m2,type="III") anv1 give me correct result anv2's result similar to Anova(m1, type="III") Can anyone please explain why? Thanks, Yonggan [[alternative HTML version deleted]]

Hi Yonggan, This has nothing to do with Bioconductor, so you should ask elsewhere. Note that type III models have been beat to death on R-help, so a simple search of that list's archive would be likely to answer your question. Best, Jim On 6/19/2012 11:52 AM, Yonggan Wu wrote: > Hi, > > I just found out type III ANOVA won't give me model comparison result, > am I not suppose to do model comparison with type III ANOVA? > > Say we have two models > m1=lm(data~factor1+factor2,data=table) > m2=lm(data~factor1*factor2,data=table) > > Type I ANOVA comparison > anv1=anova(m1,m2) > > Type III ANOVA Comparison, from car package > anv2=Anova(m1,m2,type="III") > > anv1 give me correct result > anv2's result similar to Anova(m1, type="III") > > Can anyone please explain why? > > Thanks, > Yonggan > > [[alternative HTML version deleted]] > > _______________________________________________ > Bioconductor mailing list > Bioconductor at r-project.org > https://stat.ethz.ch/mailman/listinfo/bioconductor > Search the archives: http://news.gmane.org/gmane.science.biology.informatics.conductor -- James W. MacDonald, M.S. Biostatistician University of Washington Environmental and Occupational Health Sciences 4225 Roosevelt Way NE, # 100 Seattle WA 98105-6099