[R] Singularity in simple ANCOVA problem

[Robert A LaBudde]

At 08:44 PM 6/20/2010, RICHARD M. HEIBERGER wrote:
>You have only one Age value in each Lot.  Hence the Age is aliased 
>with one of the
>5 degrees of freedom between lots.  You can see it in the picture
>
>xyplot(Conc ~ Age|Lot, data=blots, pch=16)
>
>There is no opportunity for a slope within each of the groups.
>
>Rich

Doh!

Thanks.

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Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral at lcfltd.com
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