Statistical FAQs

I am fitting a model with random effects using the expected mean squares method. When I look at the "Test denominator synthesis" output, some effects are not being tested as I think they should. Is JMP calculating these tests incorrectly?

No, this issue is an item of controversy among statisticians and relates to the formulation and parameterization of the model. JMP is following the references of Hocking and Hartley and Searle (listed below) to determine appropriate error terms in models with random effects.

Hocking, R.R. (1973), "A Discussion of the Two-Way Mixed Model," THE AMERICAN STATISTICIAN, 27, 148-152.
Hartley, H.O. and Searle, S.R. (1969), "A Discontinuity in Mixed Model Analysis," BIOMETRICS, 25, 573-576.

FAQ # 1467
Last Updated: 2002 Nov 22

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Statistical FAQs

I am fitting a model with random effects using the expected mean squares method. When I look at the "Test denominator synthesis" output, some effects are not being tested as I think they should. Is JMP calculating these tests incorrectly?

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