overdispersion

  1. E

    SAS glimmix overdispersion

    Let's say I have an experiment with a total of 10 petridishes each with 20 seeds. 5 of these petri dishes are variety A and 5 are variety B. I count the number of germinated seeds in each dish. There seems to be to be two main ways to model potential over dispersion: proc glimmix data=a...
  2. L

    Adjust for overdispersion in glm family = binomial (logit) model

    I have an overdispersion problem in my model.. I have the following data: y= succes/fail (%) x= Var1 : Temperature data m1<-glm(cbind(succes,fail)~Var1, data=data, family = binomial(logit)) Call: glm(formula = cbind(succes, fail) ~ Var1, family = binomial(logit), data = data)...
  3. N

    multinomial logistic regression - assumptions violated?

    Hi everybody :) I ended up asking a few questions in another thread that however didn't have a matching title, which probably explains why nobody replies. Since it's really important for me to understand, I am reposting my questions in this new thread with a matching title... and hope someone...
  4. N

    Advice in Generalized Linear Models (Toxicology Study)

    Hi all, I’m new here, and fairly new to GLMMs. I’m using PROC GENMOD to model a count outcome (number of offspring) in a toxicology study. Offspring count data were collected in 10 equally spaced time points for every individual (subject) in the experiment. Besides “time”, I have a nominal...