On Mar 18, 2012, at 08:21 , shoreliner11 wrote: > I'm still relatively new to R but was wondering if anyone could help me force > R to compute the f-statistic etc using the the nested term rather than the > residual. In my particular case we were nesting a treatment effect by a > replicated tank which was not non-significant enough (p>0.25)to be dropped > from the statistical model.
Ouch!!!!! Don't _ever_ take high p-values as proof of absence of effect. > > Here's my code: > summary(analysis1<-aov(Area~Treatment/Tank)) > > Area is the response variable, treatment is the main effect, nested within a > replicated tank. Thanks so much for your help. > I.e. Tanks are numbered within Treatments, so that Treatment 1, Tank 1 is distinct from Treatment 2, Tank 1? Something like aov(Area~Treatment + Error(Treatment:Tank)) should do it. There's a wart in aov() causing this sort of model to throw a warning that "Error() model is singular", for reasons that I never quite fathomed. An explicit TrTa <- interaction(Treatment,Tank) and then using Error(TrTa) gets rid of the warning and provides equivalent output. > -- > View this message in context: > http://r.789695.n4.nabble.com/ANOVA-testing-over-nested-MS-term-tp4481767p4481767.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. -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.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.
