[R] Help with logistic model with random effects in R

LAURA WEIR 0611792W at student.gla.ac.uk
Wed Jan 19 20:24:54 CET 2011


Hello everyone, 

I'm quite new to R and am trying to run a logistic model to look at how various measures of boldness in individual animals influences probability of capture, however I also want to include random effects and I'm not sure how to construct a model that incorporates both of these things. 

Data was collected from 6 different groups of 6 individuals with 10 replicates for each group. Whether an individual was caught in a trial or not was called "Catchability" and the outcome is binomial (caught = 1, not caught = 0). "Catchability" is my response variable that I want to see if I can explain by the other variables. "Individual" and "Group" would be my random effects. I have already installed lme4 but not sure how to code for the model I need, can anyone offer any help please?

The column headings in my data table are as follows.

 [1] "Trial"          "Group"          "Individual"     "Mark"          
 [5] "Catchability"   "Mboldness1"     "Mboldness2"     "Nboldness1"    
 [9] "Nboldness2"     "Standardlength"


This is the string of my data:

str(data)
'data.frame':   36 obs. of  10 variables:
 $ Trial         : int  1 2 3 4 5 6 7 8 9 10 ...
 $ Group         : int  1 1 1 1 1 1 2 2 2 2 ...
 $ Individual    : int  1 2 3 4 5 6 7 8 9 10 ...
 $ Mark          : Factor w/ 8 levels " - O"," - P",..: 8 2 4 6 3 1 6 3 1 5 ...
 $ Catchability  : int  1 1 1 1 0 1 1 1 1 1 ...
 $ Mboldness1    : int  7 10 0 11 15 5 15 4 15 1 ...
 $ Mboldness2    : int  1 270 600 1 10 203 10 230 1 580 ...
 $ Nboldness1    : int  0 0 0 0 0 0 1 0 2 0 ...
 $ Nboldness2    : int  270 110 50 50 90 70 130 90 260 220 ...
 $ Standardlength: num  40.5 37.4 38.6 41.1 39.1 40.5 50.2 60.3 53.9 55 ...


Many thanks in advance,

Laura


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