2-way anova on unbalanced dataset

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Published on 2010-04-12T19:15:01Z Indexed on 2010/04/13 7:13 UTC
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Is aov appropriate for unbalanced datasets. According to help ...provides a wrapper to lm for fitting linear models to balanced or unbalanced experimental designs. But later on it says aov is designed for balanced designs, and the results can be hard to interpret without balance.

How should I perform a 2-way anova on an unbalanced dataset in R?

I would like to reproduce the different results for type I and type III sum of squares of SAS output (when using proc glm). I remember we were using type III sum of squares for unbalanced datasets.

Thank you in advance.

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