[R] marginality principle / selecting the right type of SS for an interaction hypothesis

[hadley wickham]

> BTW, although I didn't read it carefully, the your web-page description of a
> main effect in the presence of an interaction appears to imply that this
> averages across all individuals, when in fact it averages across the levels
> of the other factor; the result is different when there are unequal numbers
> of observations in the cells. As well, you describe the model in your email
> as an ANCOVA, when in fact it appears to be a two-way ANOVA.

And why not show the raw data on the model summary plots?  That way
you could spot potential outliers, or skewness etc.

Hadley


-- 
http://had.co.nz/