Inadmissibility of Studentized Tests for Normal Order Restricted Models
Cohen, Arthur ; Sackrowitz, H. B.
Ann. Statist., Tome 21 (1993) no. 1, p. 746-752 / Harvested from Project Euclid
Consider the model where $X_{ij}, i = 1,\ldots, k; j = 1,2,\ldots, n_i; n_i \geq 2$, are observed. Here $X_{ij}$ are independent $N(\theta_i,\sigma^2), \theta_i, \sigma^2$ unknown. Let $X_i = \sum^n_{j = 1}X_{ij}/n_i, \mathbf{X}' = (X_1,\ldots, X_k), \mathbf{\theta}' = (\theta_1,\ldots,\theta_k), V = \sum^k_{i = 1} \sum^{n_i}_{j = 1}X^2_{ij} - n \sum^k_{i = 1}X^2_i$. Let $\mathbf{A}_1$ be a $(k - m) \times k$ matrix of rank $(k - m) \geq 2$ and test $H: \mathbf{A}_1\mathbf{\theta} = \mathbf{0}$ versus $K - H$ where $K: \mathbf{A}_1\mathbf{\theta} \geq \mathbf{0}$. Suppose we assume $\sigma^2$ known and consider a constant size $\alpha$ test $(\alpha < 1/2)$ which is admissible for $H$ versus $K - H$ based on $\mathbf{X}$. Next assume $\sigma^2$ is unknown. Consider the same test but now as a function of $\mathbf{X}/V^{1/2}$ (i.e., Studentize the test). The resulting test is inadmissible. Examples are noted.
Publié le : 1993-06-14
Classification:  Inadmissibility,  order restricted alternatives,  complete class,  Dunnett's test,  62F03,  62C15
@article{1176349148,
     author = {Cohen, Arthur and Sackrowitz, H. B.},
     title = {Inadmissibility of Studentized Tests for Normal Order Restricted Models},
     journal = {Ann. Statist.},
     volume = {21},
     number = {1},
     year = {1993},
     pages = { 746-752},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1176349148}
}
Cohen, Arthur; Sackrowitz, H. B. Inadmissibility of Studentized Tests for Normal Order Restricted Models. Ann. Statist., Tome 21 (1993) no. 1, pp.  746-752. http://gdmltest.u-ga.fr/item/1176349148/