I'm really puzzled to know what has caused the sudden rush on these kinds of questions.
> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Sent: Saturday, March 08, 2003 1:27 AM > To: [EMAIL PROTECTED] > Subject: [R] Type IV sum of squares > > To anyone who can help: > > I am trying to do an analysis of variance with a very unbalanced design > and a few empty cells. How do I get R to use type III and more > importantly type IV sums of squares? > [WNV] My friendly advice is forget all that malarkey, and even forget about putting it all in one big analysis of variance table. Calmly decide which null hypotheses you want to test within which outer hypotheses, fit each null and each outer model, separately if necessary, test them using anova( ) and report your results. Unbalanced designs and empty cells do not alter the general procedure you should adopt one bit. All they do is change the power of the test, a fact of which you should be well aware, of course. (In fact if the design is really deficient you may find that you have a reduncancy and cannot perform some of your tests, but that is a side issue and no 'Types' of sums of squares can ever fix it - you need a better design to make any progress. ) Hard as it may be to accept, that whole business of Type ? sums of squares is a gigantic red herring and a distinction without a difference. It would truly have been better if the concepts were never invented and certainly not inflicted on a naive and unsuspecting whole statistical generation. This is one situation where curiously the reality is much simpler than it might seem from some of the propaganda. Trust me: I'm a statistician... > Thanks > > Deven Hamilton > Department of Sociology > University of Washington > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
