[R] nested, unbalanced anova

peter dalgaard pdalgd at gmail.com
Sun Jan 6 19:55:58 CET 2013

On Jan 6, 2013, at 09:45 , peter dalgaard wrote:

> Just avoid things like Type-III sums of squares (base R won't do them, but popular add-ons will) because they get it wrong when cell counts are unequal.

That might be a bit unfair. Type-III methodology has its proponents, I'm just not one of them. Within their own logic, I'm sure Type-III SS are computed correctly. It's just that this is one of the cases where you can be misled into thinking that the design is orthogonal so Type-III and Type-II is the same. It isn't.

Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com

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