All Questions
14 questions
2
votes
1
answer
164
views
Glmer with count data, repeat measurements and how to interpret output
I'm very new to mixed models (this is my first attempt) and have about 2 months experience in R so please forgive my ignorance. I am seeking guidance on my current project analysing the relationship ...
- 23
0
votes
1
answer
54
views
random slopes by two groups (species and site)?
I have a dataset of 20 bird species counted at 8 sites, and I'd like to estimate the species-specific change in migration timing at each site. Roughly half of those species are recorded at >= 5 ...
- 255
3
votes
0
answers
3k
views
What distribution to use for left-skewed data in generalized linear mixed models (for use with structural equation modelling)?
I'm trying to run a GLMM with a response variable that is left-skewed. Eventually this model will form part of a piecewise structural equation model (using piecewiseSEM).
I have data from 480 plots, ...
- 142
1
vote
0
answers
177
views
Doubts about the use of Cross-Validation in GLMM
I've recently ask in statckoverflow about some doubts with logistic regression fitted with a GLMM and an user recommend me asking in this forum. So, here it goes.
I work with a wild population of a ...
- 11
0
votes
1
answer
216
views
Model specification in nlme: Random effects
My design has a total of 20 sites. 5 sites belong to each of four land covers: A, B, C and D. In each site, I have 5 sampling locations, 2 metres from each other. From each sampling location, I ...
7
votes
2
answers
395
views
Don't understand why glmm random effect variance is zero. Have reviewed similar questions still dont get it
I study a colonially-nesting bird species. I am trying to perform an AICc evaluation of GLMMs for a nest site selection study. I collected data at nest sites and paired random sites. I want to ...
- 83
3
votes
1
answer
2k
views
Fitting and interpreting random effects in repeated measures and unbalanced ecological data set
I have a vegetation data set that consists of 150 plots that were sampled 1-3 times over a three year period. Plots are my unit of observation and they are unbalanced (since plots were sampled either ...
- 31
5
votes
2
answers
3k
views
GLMM- relationship between AICc weight and random effects?
I am developing GLMM's in order to assess habitat selection (using GLMMs' coeficients to construct Resource selection functions).
I have (telemetry) data from 5 study areas, and each area has a ...
- 637
2
votes
2
answers
2k
views
GLMM: relationship between AIC, R squared and overdispersion?
First of all, I am a beginner in statistics, and I have been reading some questions and comments here regarding this matter but I am still a bit lost.
My problem:
I am constructing GLMM's in order to ...
- 637
4
votes
1
answer
290
views
Multivariate Analysis of Ecological Data: Procrustes analyses or GLM?
I have a dataset containing 6 variables (vegetation cover in percent) and the number of species found in 30 areas.
I would like to test if the different vegetation covers explain species richness.
...
- 141
1
vote
1
answer
1k
views
GLMM or LME? Repeated measures help?
I am having trouble using the correct test and r code for my experiment. Essentially I measured insect emergence daily from artificial streams with 3 treatments.:
...
- 11
2
votes
2
answers
2k
views
mixed effects and lme4: Do I need nesting?
I am analyzing data from a field experiment, and I am interested in the effects of fauna and altitude (fixed). Altitude has two levels, and at each site I have 5 blocks for the three levels of fauna (...
18
votes
4
answers
28k
views
Interpreting random effect variance in glmer
I'm revising a paper on pollination, where the data are binomially distributed (fruit matures or does not). So I used glmer with one random effect (individual plant)...
- 313
2
votes
1
answer
275
views
Intraspecific variation in MCMCglmm
I want to use MCMCglmm to account for phylogenetic autocorrelation on my GLMM. However I have more than one trait measurement for certain species.
Is there a way ...
- 151