[R] Testing equality of regression model on multiple groups

[David Winsemius]

On Dec 17, 2009, at 5:14 PM, Clara Yuan wrote:

> Hello,
>
>

>
> (Also, why are the coefficients renamed to t.L, t.Q, etc instead of  
> t.1, t.2?)

You have coded your t variable as an ordered factor.

?ordered

if you do not want the linear, quadratic, cubic coefficients for the  
polynomial contrasts, then remove the ordering with:

t <- factor(t, is.ordered=FALSE)

... and rerun the analysis.

-- 
David

>
> What am I missing?
>
> Thanks for the help,
> Clara
>
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT