[R] Three-way ANOVA shows me two-way results

Marius 't Hart
Tue, 23 Nov 2010 13:46:44 -0000

Hi all,

I'm doing a 3-way ANOVA like this:

summary(aov(formula('FP ~ (lum * obj * man)^3 - Error(vp/(lum * obj *
man)^3)'),data=dataf))

But in the output I only get 1- and 2-way effects, like this one:

Error: vp:obj:man
Df Sum Sq Mean Sq F value Pr(>F)
obj:man 1 1.5291e-34 1.5291e-34 5.7011 0.0542 .
Residuals 6 1.6093e-34 2.6822e-35
---
Signif. codes: 0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1

(And a warning that the Error() model is singular.)

What am I doing wrong so that I don't get the 3-way interactions I want
to look at?

Thank you!

Marius.