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作者：Zhou, Lan; Huang, Jianhua Z.; Carroll, Raymond J.
作者单位：Texas A&M University System; Texas A&M University College Station
摘要：We propose a modelling framework to study the relationship between two paired longitudinally observed variables. The data for each variable are viewed as smooth curves measured at discrete time-points plus random errors. While the curves for each variable are summarized using a few important principal components, the association of the two longitudinal variables is modelled through the association of the principal component scores. We use penalized splines to model the mean curves and the prin...
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作者：Diciccio, Thomas J.; Young, Alastair
作者单位：Cornell University; Imperial College London
摘要：Higher-order inference about a scalar parameter in the presence of nuisance parameters can be achieved by bootstrapping, in circumstances where the parameter of interest is a component of the canonical parameter in a full exponential family. The optimal test, which is approximated, is a conditional one based on conditioning on the sufficient statistic for the nuisance parameter. A bootstrap procedure that ignores the conditioning is shown to have desirable conditional properties in providing t...
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作者：Wang, Qihua; Dai, Pengjie
作者单位：Chinese Academy of Sciences; Academy of Mathematics & System Sciences, CAS
摘要：We consider a semiparametric model that parameterizes the conditional density of the response, given covariates, but allows the marginal distribution of the covariates to be completely arbitrary. Responses may be missing. A likelihood-based imputation estimator and a semi-empirical-likelihood-based estimator for the parameter vector describing the conditional density are defined and proved to be asymptotically normal. Semi-empirical loglikelihood functions for the parameter vector and the resp...
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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：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：Chang, Ted; Kott, Phillip S.
作者单位：University of Virginia
摘要：When we estimate the population total for a survey variable or variables, calibration forces the weighted estimates of certain covariates to match known or alternatively estimated population totals called benchmarks. Calibration can be used to correct for sample-survey nonresponse, or for coverage error resulting from frame undercoverage or unit duplication. The quasi-randomization theory supporting its use in nonresponse adjustment treats response as an additional phase of random sampling. Th...
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作者：Crainiceanu, Ciprian M.; Dominici, Francesca; Parmigiani, Giovanni
作者单位：Johns Hopkins University; Johns Hopkins University
摘要：Often there is substantial uncertainty in the selection of confounders when estimating the association between an exposure and health. We define this type of uncertainty as 'adjustment uncertainty'. We propose a general statistical framework for handling adjustment uncertainty in exposure effect estimation for a large number of confounders, we describe a specific implementation, and we develop associated visualization tools. Theoretical results and simulation studies show that the proposed met...
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作者：Nedyalkova, Desislava; Tille, Yves
作者单位：University of Neuchatel
摘要：In some cases model-based and model-assisted inferences can lead to very different estimators. These two paradigms are not so different if we search for an optimal strategy rather than just an optimal estimator, a strategy being a pair composed of a sampling design and an estimator. We show that, under a linear model, the optimal model-assisted strategy consists of a balanced sampling design with inclusion probabilities that are proportional to the standard deviations of the errors of the mode...
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作者：Westfall, Peter H.
作者单位：Texas Tech University System; Texas Tech University
摘要：Benjamini and Hochberg's method for controlling the false discovery rate is applied to the problem of testing infinitely many contrasts in linear models. Exact, easily calculated critical values are derived, defining a new multiple comparisons method for testing contrasts in linear models. The method is adaptive, depending on the data through the F-statistic, like the Waller-Duncan Bayesian multiple comparisons method. Comparisons with Scheffe's method are given, and the method is extended to ...
