Abstract
The general mixed linear model can be written y = Xβ + Zu + e, where β is a vector of fixed effects, u is a vector of random effects and e is a vector of random errors. In this note, we mainly aim at investigating the general necessary and sufficient conditions under which the best linear unbiased estimator for \({\varvec \varrho}({\varvec l}, {\varvec m}) = {\varvec l}{\varvec '}{\varvec \beta}+{\varvec m}{\varvec '}{\varvec u}\) is also optimal under the misspecified model. In addition, we offer approximate conclusions in some special situations including a random regression model.
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This research was partially supported by Grants HGQ0637 and HGQN0725 from Huaiyin Institute of Technology. The second author was supported the “Green & Blue Project” Program for 2008 to Cultivate Young Core Instructors.
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Rong, JY., Liu, XQ. On misspecification of the dispersion matrix in mixed linear models. Stat Papers 51, 445–453 (2010). https://doi.org/10.1007/s00362-009-0213-0
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DOI: https://doi.org/10.1007/s00362-009-0213-0
Keywords
- Mixed linear model
- True model
- Misspecified model
- Dispersion
- Random regression coefficient model
- Compound symmetric