I tried to use tweedie and it again worked very well for the most abundant pollen types and when trying to fit the less abundant ones I got the error: "glm.fit:
algorithm did not converge".
I have the impress that it is hopeless to try fitting a model...But anyway thank you very much for making me aware of tweedie. I still should go a bit more into the
theorical background. I just wonder about the residuals. For the pollen types that can be modelled, the QQ-plots don't look very nice, but the residuals are relatively
well homogeneously distributed. It is difficult to judge how good the fit is, but the results make sense in regard to the raw data.
Val?rie
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