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New heterogeneous test statistics for the unbalanced fixed-effect nested design
Jiin-Huarng Guo1, L Billard, Wei-Ming Luh
1Department of Applied Mathematics, National Pingtung University of Education, Pingtung City, Taiwan.
Abstract:
When the underlying variances are unknown or/and unequal, using the conventional F test is problematic in the two-factor hierarchical data structure. Prompted by the approximate test statistics (Welch and Alexander-Govern methods), the authors develop four new heterogeneous test statistics to test factor A and factor B nested within A for the unbalanced fixed-effect two-stage nested design under variance heterogeneity. The actual significance levels and statistical power of the test statistics were compared in a simulation study. The results show that the proposed procedures maintain better Type I error rate control and have greater statistical power than those obtained by the conventional F test in various conditions. Therefore, the proposed test statistics are recommended in terms of robustness and easy implementation.
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