On 4/11/07, Brendan Connors <[EMAIL PROTECTED]> wrote: > Hi R-users: > > New to R and I am trying to run a GLM with random effects. > > I have 3 replicates ('Replicate) of counts of parasites ('nor.tot.lep') > before and after an experiment ('In.Out'). When I run lmer I get the > error messages (16 of each) below... > > > lmer(nor.tot.lep ~ In.Out + (In.Out|Replicate),data=coho, family > =tweedie(var.power = 1, > + link.power = 1)) > Generalized linear mixed model fit using PQL > Formula: nor.tot.lep ~ In.Out + (In.Out | Replicate) > Data: coho > Family: Tweedie(mu^1 link) > AIC BIC logLik deviance > 849.2 867.4 -419.6 839.2 > Random effects: > Groups Name Variance Std.Dev. Corr > Replicate (Intercept) 0.78861 0.88804 > In.Out 0.67232 0.81995 -1.000 > Residual 2.96308 1.72136 > number of obs: 279, groups: Replicate, 3
According to this summary you have 3 distinct replicates and you are trying to use those three replicates to estimate 3 variance-covariance parameters. It won't work. Notice that the estimated correlation is -1.000. Your estimated variance-covariance matrix is singular. > > Fixed effects: > Estimate Std. Error t value > (Intercept) -0.2431 0.6619 -0.3672 > In.Out 1.6004 0.5645 2.8349 > > Correlation of Fixed Effects: > (Intr) > In.Out -0.975 > There were 30 warnings (use warnings() to see them) > > > warnings() > Warning messages: > 1: Estimated variance-covariance for factor 'Replicate' is singular > in: LMEopt(x = mer, value = cv) > 2: nlminb returned message false convergence (8) > in: LMEopt(x = mer, value = cv) > > I have made sure I have the latest lme4 version, any help would be much > appreciated. > > Cheers, > > Brendan Connors > Behavioural Ecology Research Group > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.