[R] a-priori orthogonal contrasts

Keith Alan Chamberlain Keith.Chamberlain at Colorado.EDU
Tue Jun 26 03:29:18 CEST 2007


Dear R-helpers,

I have some stacked data with which I want to generate orthogonal contrasts - with the caveat that I determine what means comparisons are taking place a-priori.

Does it matter for e.g. 'contr.SUM' that the data are stacked, and does 'contr.SUM' allow me to set the contrasts efficiently even if the data are unballanced? Is there an alternative in R I should consider?

Sincerely,
KeithC.
Psych Undergrad, CU Boulder (US)



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