Dear R List -

I am trying to do a relatively simple GLMM but am having a problem. 

My data is categorical but converted to numeric form in excel ( i.e a=1, b=2 etc) my response is binary and i have two random terms - FAMILY and ORDER.

I have been running the model fine calling this -

model2 <- lmer(THREAT~1+(1|ORDER/FAMILY) + BREEDING_SYSTEM*LIFE_FORM + WOODY_NONWOODY, family=binomial)

Fixed effects:
                          Estimate Std. Error z value Pr(>|z|)   
(Intercept)                2.62364    1.41554   1.853  0.06382 . 
BREEDING_SYSTEM           -1.24256    0.47227  -2.631  0.00851 **
LIFE_FORM                 -0.64368    0.29026  -2.218  0.02659 * 
WOODY_NONWOODY             0.51817    0.19548   2.651  0.00803 **
BREEDING_SYSTEM:LIFE_FORM  0.22289    0.09842   2.265  0.02353 * 

However i want to know what type of life form, breeding system etc is significant so i called -

woodynonwoody <- as.factor(WOODY_NONWOODY)
habit <- as.factor(HABIT)
breedingsystem <- as.factor(BREEDING_SYSTEM)

model3 <- lmer(THREAT~1+(1|ORDER/FAMILY) + breedingsystem + woodynonwoody*habit, family=binomial)
Warning message:
In mer_finalize(ans) : gr cannot be computed at initial par (65)

model3
Error in asMethod(object) : matrix is not symmetric [1,2]

Interestingly when i try the above call without the interaction term it works


Any help would be greatly appreciated

Chris


> sessionInfo()
R version 2.11.1 (2010-05-31) 
i386-apple-darwin9.8.0 

locale:
[1] en_GB.UTF-8/en_GB.UTF-8/C/C/en_GB.UTF-8/en_GB.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] perturb_2.03       lme4_0.999375-34   Matrix_0.999375-40 lattice_0.18-8    

loaded via a namespace (and not attached):
[1] grid_2.11.1   nlme_3.1-96   stats4_2.11.1 tools_2.11.1


Chris Mcowen
PhD Student

Room 15
Sir Harold Mitchell Building
University of St Andrews
St Andrews
Fife
KY16 9TH
UK
Phone 01334 463381 


	[[alternative HTML version deleted]]


