Mixed model parameterization

Aggregating the data will remove al lot of information. And might introduce
bias in case of an unbalanced design.

You need to think about the (combination of) variables which have a common
effect. (1|plot) + (1|plot:hour) assumes a plot effect and an effect of
each combination of plot and hour, but no common hour effect.

Days are nested in months. The corresponding random effect is (1|month) +
(1|month:day). You have (1|day) + (1|day:month) which is nonsense.

You really need to do some reading on mixed models. I recommend Zuur et al
(2009) Mixed Effects Models and Extensions in Ecology with R

ir. Thierry Onkelinx
Statisticus / Statistician

Vlaamse Overheid / Government of Flanders
INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND
FOREST
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
thierry.onkelinx at inbo.be
Havenlaan 88 bus 73, 1000 Brussel
www.inbo.be

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Op ma 20 mei 2019 om 16:07 schreef Salvador S?nchez-Col?n <
salvadorsanchezcolon at prodigy.net.mx>:

Mixed model parameterization

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