Mixed effects model with binomial errors - problem
anyone?
RFTW wrote:
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
summary(model1<-lmer(cbind(VisitsExpTree,TotalVisits-VisitsExpTree)~ treatment +(1|Individual), family=binomial, data=r))
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
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