Message-ID: <1349438507759-4645150.post@n4.nabble.com>
Date: 2012-10-05T12:01:47Z
From: autarkie
Subject: Setting the desired reference category with contr.sum
Hi,
I have 6 career types, represented as a factor in R, coded from 1 to 6. I
need to use the effect coding (also known as deviation coding) which is
normally done by contr.sum, e.g.
contrasts(career) <- contr.sum(6)
However, this results in the 6th category being the reference, that is being
coded as -1:
$contrasts
[,1] [,2] [,3] [,4] [,5]
1 1 0 0 0 0
2 0 1 0 0 0
3 0 0 1 0 0
4 0 0 0 1 0
5 0 0 0 0 1
6 -1 -1 -1 -1 -1
In fact, I need number 1 to be the reference. How do I achieve that? Thank
you.
Regards,
Maxim
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