[R-sig-ME] Stratification in a mixed model

[ONKELINX, Thierry]

Dear all,

We have data from a study with 6 strata. The small strata are oversampled and the large strata undersampled. The locations are revisited every three years. Our basic model is glmer(Count ~ factor(Year) + (1|Location), family = poisson). 

Can we take the over- and undersampling into account with the weights argument? Do we have to standardise the weights? E.g. the sum of all the weights = 1, or the sum of the weights per 3 year cycle = 1, or the sum of the weights per year = 1

Best regards,

Thierry 

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ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek
team Biometrie & Kwaliteitszorg
Gaverstraat 4
9500 Geraardsbergen
Belgium

Research Institute for Nature and Forest
team Biometrics & Quality Assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium

tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be
www.inbo.be

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~ Sir Ronald Aylmer Fisher

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