[R-sig-ME] Jointly testing several parameters of factor variable

Stijn Ruiter s.ruiter at maw.ru.nl
Sat Jan 31 12:30:46 CET 2009

Hi all,
I am estimating a lmer model and now I would like to test whether some
coefficients for specific levels of factor variable are equal.
I am thinking of either:
(1) applying equality constraints on several parameters for specific
levels of a factor variable (and use that to do LRT against model
without equality constraints), but I have no clue on how to that; or
(2) do a Wald test in which several parameter estimates of a factor
variable are jointly tested. Although I noticed "wald.test" from the
"aod" package, but I don't quite follow how to apply that to my lmer model.

Any suggestions on how to jointly test several parameters of a lmer
model (preferably applied to factor variables)?


Best regards,

Stijn Ruiter
Department of Sociology / ICS
Radboud University Nijmegen
P.O. Box 9104
6500 HE Nijmegen

Phone: + 31 24 361 2272
Fax:   + 31 24 361 2399

Visiting address:
Thomas van Aquinostraat 4.01.71

website: http://oase.uci.ru.nl/~sruiter

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