[R] mantelhaen.test for more than two groups?

[Peter Dalgaard]

Thomas Lumley <tlumley at u.washington.edu> writes:

> On Tue, 26 Apr 2005, Katrin Schweitzer wrote:
> 
> > Dear All,
> >
> > I'd like to perform the generalized Cochran-Mantel-Haenszel-Test (as
> > described in Agresti (1990), Categorical Data Analysis) for my
> > nominal data.
> >
> > My problem is that I have more than two groups. In fact I think I'd
> > need an 5-dimensional array for the response variable, the control
> > variable and three group variables.
> > Could you please tell me if this is possible in R - and if yes how I
> > am supposed to do this?
> 
> You're supposed to have a three-dimensional array: exposure x response
> x group.
> 
> This means turning your three group variables into one variable.  One
> way to do this is with the interaction() function.

Or, if data are already counts, change the dimensions (as in dim(x) <-
c(2,3,8)), possibly after using aperm() to get the indices in the
right order.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
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