[R] fit.contrast error

From: Dani Valverde <daniel.valverde_at_uab.cat>
Date: Fri, 06 Jun 2008 18:32:14 +0200


Hello,
I am trying to perform a fit.contrast() on a lme object with this code:

attach(error_DB)
model_temperature <- lme(Error ~ Temperature, data = error_DB,random=~1|ID) summary(model_temperature)
fit.contrast(model_temperature, "Temperature", c(-1,1), conf.int=0.95 ) detach(error_DB)

but I got this error

Error in `contrasts<-`(`*tmp*`, value = c(-0.5, 0.5)) :   contrasts apply only to factors

My database is a dataframe, very similar to that of the Orthodont. Could anyone give me some advise on how to solve the problem?

Best,

Dani

-- 
Daniel Valverde Saubí

Grup de Biologia Molecular de Llevats
Facultat de Veterinària de la Universitat Autònoma de Barcelona
Edifici V, Campus UAB
08193 Cerdanyola del Vallès- SPAIN

Centro de Investigación Biomédica en Red
en Bioingeniería, Biomateriales y
Nanomedicina (CIBER-BBN)

Grup d'Aplicacions Biomèdiques de la RMN
Facultat de Biociències
Universitat Autònoma de Barcelona
Edifici Cs, Campus UAB
08193 Cerdanyola del Vallès- SPAIN
+34 93 5814126

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Received on Fri 06 Jun 2008 - 16:56:35 GMT

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