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Mixed effects model with binomial errors - problem

RFTW 
ok... the model now runs properly (say, without errors). Now about the
result.
These are the averages per treatments

tapply(VecesArbolCo.VecesCo.C1,T2,mean)
  a     b      c     d 
0.49 0.56 0.45 0.58 


I run this very simple model
Generalized linear mixed model fit by the Laplace approximation 
Formula: cbind(VisitsExpTree,TotalVisits-VisitsExpTree)~ treatment
+(1|Individual)  
   Data: r 
   AIC   BIC logLik deviance
 242.3 255.9 -116.2    232.3
Random effects:
 Groups    Name        Variance Std.Dev.
 Individuo (Intercept) 0.14075  0.37517 
Number of obs: 112, groups: Individuo, 37

Fixed effects:
            Estimate Std. Error z value Pr(>|z|)   
(Intercept)          0.37228    0.19031  1.9562  0.05044 . 
treatmentb          0.03367    0.24520  0.1373  0.89079   
treatmentc         -0.60606    0.23330 -2.5978  0.00938 **
treatmentd         -0.25504    0.22790 -1.1191  0.26311   
---
Signif. codes:  0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1 

Correlation of Fixed Effects:
    (Intr) T2b    T2c   
T2b -0.675              
T2c -0.697  0.543       
T2d -0.720  0.544  0.581


wouldnt we expect the intercept to be roughtly the mean of treatment a? and
thus the estimate of treatmentb to be +0.07, c: -0.04 and d: +0.09 roughly?

Is this model just completely not estimating well, or are the estimates not
the 'real values'. 

I tried to get teh predict function to give me the 4 predicted values based
on the model, but i havent succeeded in doing so. maybe someone can help me
on that one too (predict(model1,type="response") doesnt work)

thnx

Thread (7 messages)

RFTW Mixed effects model with binomial errors - problem Sep 10 Ben Bolker Mixed effects model with binomial errors - problem Sep 10 RFTW Mixed effects model with binomial errors - problem Sep 10 Ben Bolker Mixed effects model with binomial errors - problem Sep 10 RFTW Mixed effects model with binomial errors - problem Sep 11 RFTW Mixed effects model with binomial errors - problem Sep 18 ONKELINX, Thierry Mixed effects model with binomial errors - problem Sep 19