Hi R-people,

 I performed controlled experiments to evaluated the seeds germination of
two palms under four levels of water treatments. I conducted a generalized
linear model (GLM) with a Poisson distribution to verify whether there were
significant differences in the number of seed germination (NS-count
variable)  between treatments and species (explanatory variables). Thus, my
model and output were:

model1<-glm(NS~Treatments*Species, family="poisson")



Coefficients:

                               Estimate  Std. Error  z value  Pr(>|z|)

(Intercept)               2.56247    0.57544   4.453    8.46e-06 ***

Treatments              -2.07267    0.35065  -5.911   3.40e-09 ***

Species                     -0.00312    0.30527  -0.010  0.992

Treatments:Species     0.90397    0.17896   5.051  4.39e-07 ***

 Null deviance: 379.870  on 98  degrees of freedom

Residual deviance:  68.302  on 95  degrees of freedom



There is a significant interaction between treatments:species. Which is the
post hoc test appropriate for this model?



Thanks,

Maria Isabel

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