Dear all,
I used adonis to perform a test of the pairwise site dissimilarity indices
proposed by Baselga (2010, 2012) in the package betapart. I am concerned about
my results
because I get some negative F-values. I read in another post that this may
happen because of the presence of negative
Thank you Liz,
I don't know tweedie, I'll have a look at it, but I have indeed some high
values. I know about the problems linked to the arcsine transformation. I won't
consider it
anyway. I'd like to use either the raw values of pollen grain counts or a
logistic quasibinomial model.
Best,
Dear list members,
I am fitting a negative binomial model but I get a very large dispersion
parameter. Why is that?
quine.nb2 - glm.nb(Pt ~ Agua + Dist10, data = Abundancia)
summary(quine.nb2)
Deviance Residuals:
Min1QMedian3Q Max
-2.20911 -0.67157 0.04411
Hi Manuel,
This means that your data is closer to Poisson.
Here is an example where I simulate Poisson data and try to fit the NB
distribution. I get behavior from glm.nb that is similar to your results (large
dispersion parameter and warning about iteration limit reached).
x=rep(1:5, 10)
Hi Valerie,
The best advice I was ever given with regards to distribution was to choose the
one with the best fit i.e. no pattern in the residuals.
The 2 things to think about when fitting a GLM are the type of data you've
collected (binomial, counts etc) so that you can get an idea of which
Thank you very much Mollie.
Best,
Manuel
2013/2/3 Mollie Brooks mbro...@ufl.edu
Hi Manuel,
This means that your data is closer to Poisson.
Here is an example where I simulate Poisson data and try to fit the NB
distribution. I get behavior from glm.nb that is similar to your results
Hello List,
Is adonis capable of modeling random effects? I'm analyzing the impact of a
treatment on the microbial community in a split-plot design (2 treatments per
plot, 4 plots per grassland, 3 grasslands total). I would like to quantify how
much of the variance is due to the Treatment
