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作者：Guan, Yongtao
作者单位：Yale University
摘要：We introduce a formal testing procedure to assess the fit of an inhomogeneous spatial Poisson process model, based on a discrepancy measure function Dc( t; theta) that is constructed from residuals obtained from the fitted model. We derive the asymptotic distributional properties of Dc( t; theta) and develop a test statistic based on them. Our test statistic has a limiting standard normal distribution, so that the test can be performed by simply comparing the test statistic with readily availa...
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作者：Lu, Xiaomin; Tsiatis, Anastasios A.
作者单位：State University System of Florida; University of Florida; North Carolina State University
摘要：Under the assumption of proportional hazards, the log-rank test is optimal for testing the null hypothesis H-0 : beta = 0, where beta denotes the logarithm of the hazard ratio. However, if there are additional covariates that correlate with survival times, making use of their information will increase the efficiency of the log-rank test. We apply the theory of semiparametrics to characterize a class of regular and asymptotically linear estimators for beta when auxiliary covariates are incorpor...
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作者：Vanderweele, Tyler J.; Robins, James M.
作者单位：University of Chicago; Harvard University; Harvard T.H. Chan School of Public Health
摘要：Sufficient-component causes are discussed within the deterministic potential outcomes framework so as to formalize notions of sufficient causes, synergism and sufficient cause interactions. Doing so allows for the derivation of counterfactual and empirical conditions for detecting the presence of sufficient cause interactions. The conditions are novel in that, unlike other conditions in the literature, they make no assumption about monotonicity. The conditions can also be generalized and the c...
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作者：Fraser, D. A. S.; Rousseau, Judith
作者单位：University of Toronto; Universite PSL; Universite Paris-Dauphine
摘要：We have a statistic for assessing an observed data point relative to a statistical model but find that its distribution function depends on the parameter. To obtain the corresponding p-value, we require the minimally modified statistic that is ancillary; this process is called Studentization. We use recent likelihood theory to develop a maximal third-order ancillary; this gives immediately a candidate Studentized statistic. We show that the corresponding p-value is higher-order Un(0, 1), is eq...
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作者：Liang, Hua; Thurston, Sally W.; Ruppert, David; Apanasovich, Tatiyana; Hauser, Russ
作者单位：University of Rochester; Cornell University; Harvard University; Harvard T.H. Chan School of Public Health
摘要：We consider statistical inference for additive partial linear models when the linear covariate is measured with error. We propose attenuation-to-correction and simulation-extrapolation, SIMEX, estimators of the parameter of interest. It is shown that the first resulting estimator is asymptotically normal and requires no undersmoothing. This is an advantage of our estimator over existing backfitting-based estimators for semiparametric additive models which require undersmoothing of the nonparam...
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作者：Liang, Hua; Wu, Hulin; Zou, Guohua
作者单位：University of Rochester; Chinese Academy of Sciences; Academy of Mathematics & System Sciences, CAS
摘要：The conventional model selection criterion, the Akaike information criterion, AIC, has been applied to choose candidate models in mixed-effects models by the consideration of marginal likelihood. Vaida & Blanchard (2005) demonstrated that such a marginal AIC and its small sample correction are inappropriate when the research focus is on clusters. Correspondingly, these authors suggested the use of conditional AIC. Their conditional AIC is derived under the assumption that the variance-covarian...
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作者：Bandeen-Roche, Karen; Ning, Jing
作者单位：Johns Hopkins University; Johns Hopkins Bloomberg School of Public Health
摘要：Most research on the study of associations among paired failure times has either assumed time invariance or been based on complex measures or estimators. Little has accommodated competing risks. This paper targets the conditional cause-specific hazard ratio, henceforth called the cause-specific cross ratio, a recent modification of the conditional hazard ratio designed to accommodate competing risks data. Estimation is accomplished by an intuitive, nonparametric method that localizes Kendall's...
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作者：Cook, R. Dennis; Forzani, Liliana
作者单位：University of Minnesota System; University of Minnesota Twin Cities; National University of the Littoral; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET)
摘要：We introduce covariance reducing models for studying the sample covariance matrices of a random vector observed in different populations. The models are based on reducing the sample covariance matrices to an informational core that is sufficient to characterize the variance heterogeneity among the populations. They possess useful equivariance properties and provide a clear alternative to spectral models for covariance matrices.
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作者：Lin, Pei-Sheng
作者单位：National Chung Cheng University; National Health Research Institutes - Taiwan
摘要：We use the quasilikelihood concept to propose an estimating equation for spatial data with correlation across the study region in a multi-dimensional space. With appropriate mixing conditions, we develop a central limit theorem for a random field under various L-p metrics. The consistency and asymptotic normality of quasilikelihood estimators can then be derived. We also conduct simulations to evaluate the performance of the proposed estimating equation, and a dataset from East Lansing Woods i...
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作者：Carroll, Raymond J.; Wang, Yuedong
作者单位：Texas A&M University System; Texas A&M University College Station; University of California System; University of California Santa Barbara
摘要：We investigate the effects of measurement error on the estimation of nonparametric variance functions. We show that either ignoring measurement error or direct application of the simulation extrapolation, SIMEX, method leads to inconsistent estimators. Nevertheless, the direct SIMEX method can reduce bias relative to a naive estimator. We further propose a permutation SIMEX method that leads to consistent estimators in theory. The performance of both the SIMEX methods depends on approximations...
