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Tests of Special Structures on the Dispersion Matrix Associated with a Two‐Way Mixed Effects Model
Author(s) -
Patel H. I.,
Tsai K. T.
Publication year - 1994
Publication title -
biometrical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 63
eISSN - 1521-4036
pISSN - 0323-3847
DOI - 10.1002/bimj.4710360808
Subject(s) - random effects model , dispersion (optics) , mathematics , mixed model , matrix (chemical analysis) , random matrix , statistics , statistical physics , econometrics , physics , eigenvalues and eigenvectors , medicine , meta analysis , materials science , quantum mechanics , composite material , optics
Exact and approximate methods are available in the literature to compare the fixed effect levels in an unbalanced two‐way mixed model under the conventional distributional assumptions for random effects. However, as suggested by SHEFFÉ (1959) the conventional assumptions may not be justified in practice. Recently, KHATRI and PATEL (1992) have studied a model with an unstructured dispersion matrix associated with the random effects of which the conventional model is a special model. In this note we give likelihood ratio tests for testing some special structures on the dispersion matrix.