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作者：LEURGANS, S
作者单位：University System of Ohio; Ohio State University
摘要：Estimators for the linear model in the presence of censoring are available. A new extension of the least-squares estimator to censored data is equivalent to applying the ordinary least-squares estimator to synthetic times, time constructed by magnifying the gaps between successive order statistics. Undr suitable regularity conditions, the synthetic data estimator is Fisher consistent and asymptotically normal. Examples facilitate comparison of the synthetic data estimator with estimators propo...
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作者：BAILEY, RA
摘要：The problem of one-dimensional blocking in two-way layouts is discussed. A valid restricted randomization scheme is given for complete-block designs. This can be used to overcome the problem when the number of treatments is a prime power.
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作者：JENNISON, C
摘要：We derive group sequential tests to minimize expected sample size. A parametric family of group sequential tests is proposed containing tests which are nearly optimal, in terms of minimizing expected sample size, amongst all group sequential tests. These parametric tests can be implemented when group sizes are unequal and unpredictable. They are shown to achieve error rates close to their nominal level in a wide range of situations and to be efficient when compared with other tests based on th...
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作者：DIGGLE, PJ; GATES, DJ; STIBBARD, A
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作者：MORTON, R
作者单位：Commonwealth Scientific & Industrial Research Organisation (CSIRO)
摘要：We consider a scaled Poisson generalized linear model with random multiplicative errors associated with each stratum of a nested block structure. The normal equations are obtained. The quasi-likelihood is shown to be the product of a sequence of negative binomial quasi-likelihoods using weighted totals and correcting for margins. This is achieved by extending the definition of the quasi-likelihood which now includes a vector of weights. The usual asymptotic results still hold. Data on trap cat...
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作者：SCHOENFELD, DA; TSIATIS, AA
作者单位：Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Dana-Farber Cancer Institute
摘要：Clinical trials often employ a stratified randomization so that treatment arms are balanced within prognostic factors. In these circumstances the use of the ordinary log rank test for comparing treatment groups with respect to survival is invalid. The stratified log rank test, although valid, loses efficiency as the number of strata increases. This paper proposes a modified log rank test that is fully efficient when there is no strata effect and is more efficient than the stratified log rank t...
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作者：GUPTA, VK; NIGAM, AK
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作者：FLURY, BK
摘要：Under the common principal component model the covariance matrices .PSI.i of k populations are assumed to have identical eigenvectors, that is, the same orthogonal matrix diagonalizes all .PSI.i simultaneously. This paper modifies the common principal component model by assuming that only q out of p eigenvectors are common to all .PSI.i, while the remaining p - q eigenvectors are specific in each group. This is called a partial common principal component model. A related modification assumes t...
