Setting the desired reference category with contr.sum
Hi,
The contr. functions return matrices, so you can can create any
arbitrary matrix you like. For example
contrasts(career) <- cbind(c1=c(-1, 1, 0, 0, 0, 0),
c2=c(-1, 0, 1, 0, 0, 0),
c3=c(-1, 0, 0, 1, 0, 0),
c4=c(-1, 0, 0, 0, 1, 0),
c5=c(-1, 0, 0, 0, 0, 1))
Best,
Ista
On Fri, Oct 5, 2012 at 8:01 AM, autarkie <kovla123 at hotmail.com> wrote:
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 -- View this message in context: http://r.789695.n4.nabble.com/Setting-the-desired-reference-category-with-contr-sum-tp4645150.html Sent from the R help mailing list archive at Nabble.com.
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