Dealing with heteroscedasticity in repeated measure models
Dear list members, I am fitting a repeated measure model using lme. I have 4 measurements of a rate (variable called ipa) measured each year (variable called tempo, which was centered) on 48 counties (all the counties from a province, variable called localidad). I am considering county like a random factor. My models are: model1 = lme(ipa ~ tempo, data=ipa, random = ~1 | localidad) # random intercept model2 = lme(ipa ~ tempo, random = ~1 | tempo/localidad, data=ipa) # random intercept and slope model3 = lme(ipa ~ tempo, random = ~1 | localidad, data=ipa, correlation=corAR1(form=~ tempo)) I have heteroscedasticity. Is my last model dealing with heteroscedasticity? Thank you very much in advance. Best, Manuel
Manuel Sp?nola, Ph.D. Instituto Internacional en Conservaci?n y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspinola at una.ac.cr mspinola10 at gmail.com Tel?fono: (506) 2277-3598 Fax: (506) 2237-7036