[R] interaction effects in a Linear model

[Chuck Cleland]

On 11/23/2009 1:06 AM, ashok varma wrote:
> hello,
> 
> i am fitting a Linear model using R. I have to fit the model considering all
> the interaction effects of order 1 of the independent variables. But I have
> 9 variables. So, it will be difficult for me to write all the 36
> combinations in the model. Can anyone please help how to get this done in
> much smarter way??

  This will include all main effects and two-way interactions:

lm(Y ~ (A + B + C + D + E + F + G + H + I)^2, data=mydata)

> thanks a lot,
> Ashok Varma.
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Chuck Cleland, Ph.D.
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