[R] how to get design matrix?

Gavin Simpson gavin.simpson at ucl.ac.uk
Sun May 10 12:21:03 CEST 2009

On Sat, 2009-05-09 at 19:29 -0700, linakpl wrote:
> If I was doing an ANOVA analysis how can I get the design matrix R used?

You can do ANOVA several different ways in R, and that is just the few
functions to do this that I am aware of. Showing us what function/code
you used would be really helpful and is requested by the posting guide.

If you fitted the model using lm, then use the model.matrix method:

dat <- data.frame(Y = rnorm(100), X = gl(4,25))
mod <- lm(Y ~ X, data = dat)

This also works if you used aov()

If you used something else, then you'll have to say what...


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