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作者：Li, Wei; Gu, Yuwen; Liu, Lan
作者单位：Renmin University of China; University of Connecticut; University of Minnesota System; University of Minnesota Twin Cities
摘要：For estimating the population mean of a response variable subject to ignorable missingness, a new class of methods, called multiply robust procedures, has been proposed. The advantage of multiply robust procedures over the traditional doubly robust methods is that they permit the use of multiple candidate models for both the propensity score and the outcome regression, and they are consistent if any one of the multiple models is correctly specified, a property termed multiple robustness. This ...
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作者：Cui, Xia; Li, Runze; Yang, Guangren; Zhou, Wang
作者单位：Guangzhou University; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; Jinan University; National University of Singapore
摘要：This paper is concerned with empirical likelihood inference on the population mean when the dimension p and the sample size n satisfy p/n -> c is an element of [1, infinity). As shown in Tsao (2004), the empirical likelihood method fails with high probability when p/n > 1/2 because the convex hull of the n observations in R-p becomes too small to cover the true mean value. Moreover, when p > n, the sample covariance matrix becomes singular, and this results in the breakdown of the first sandwi...
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作者：Cao, Yuanpei; Zhang, Anru; Li, Hongzhe
作者单位：University of Pennsylvania; University of Wisconsin System; University of Wisconsin Madison
摘要：Metagenomics sequencing is routinely applied to quantify bacterial abundances in microbiome studies, where bacterial composition is estimated based on the sequencing read counts. Due to limited sequencing depth and DNA dropouts, many rare bacterial taxa might not be captured in the final sequencing reads, which results in many zero counts. Naive composition estimation using count normalization leads to many zero proportions, which tend to result in inaccurate estimates of bacterial abundance a...
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作者：Lee, A.; Whiteley, N.
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作者：Yiu, A.; Goudie, R. J. B.; Tom, B. D. M.
作者单位：MRC Biostatistics Unit; University of Cambridge
摘要：Fully Bayesian inference in the presence of unequal probability sampling requires stronger structural assumptions on the data-generating distribution than frequentist semiparametric methods, but offers the potential for improved small-sample inference and convenient evidence synthesis. We demonstrate that the Bayesian exponentially tilted empirical likelihood can be used to combine the practical benefits of Bayesian inference with the robustness and attractive large-sample properties of freque...
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作者：Mukhopadhyay, Subhadeep; Wang, Kaijun
作者单位：Pennsylvania Commonwealth System of Higher Education (PCSHE); Temple University; Fred Hutchinson Cancer Center
摘要：High-dimensional k-sample comparison is a common task in applications. We construct a class of easy-to-implement distribution-free tests based on new nonparametric tools and unexplored connections with spectral graph theory. The test is shown to have various desirable properties and a characteristic exploratory flavour that has practical consequences for statistical modelling. Numerical examples show that the proposed method works surprisingly well across a broad range of realistic situations.
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作者：Qiao, Xinghao; Qian, Cheng; James, Gareth M.; Guo, Shaojun
作者单位：University of London; London School Economics & Political Science; University of Southern California; Renmin University of China
摘要：We consider estimating a functional graphical model from multivariate functional observations. In functional data analysis, the classical assumption is that each function has been measured over a densely sampled grid. However, in practice the functions have often been observed, with measurement error, at a relatively small number of points. We propose a class of doubly functional graphical models to capture the evolving conditional dependence relationship among a large number of sparsely or de...
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作者：Wang, Y. Samuel; Drton, Mathias
作者单位：University of Chicago; Technical University of Munich
摘要：We consider graphical models based on a recursive system of linear structural equations. This implies that there is an ordering, sigma, of the variables such that each observed variable Y-v is a linear function of a variable-specific error term and the other observed variables Y-u with sigma(u) < sigma(v). The causal relationships, i.e., which other variables the linear functions depend on, can be described using a directed graph. It has previously been shown that when the variable-specific er...
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作者：Rosenbaum, P. R.
作者单位：University of Pennsylvania
摘要：In an observational study matched for observed covariates, an association between treatment received and outcome exhibited may indicate not an effect caused by the treatment, but merely some bias in the allocation of treatments to individuals within matched pairs. The evidence that distinguishes moderate biases from causal effects is unevenly dispersed among possible comparisons in an observational study: some comparisons are insensitive to larger biases than others. Intuitively, larger treatm...
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作者：Yang, S.; Pieper, K.; Cools, F.
作者单位：North Carolina State University; Duke University
摘要：Structural failure time models are causal models for estimating the effect of time-varying treatments on a survival outcome. G-estimation and artificial censoring have been proposed for estimating the model parameters in the presence of time-dependent confounding and administrative censoring. However, most existing methods require manually pre-processing data into regularly spaced data, which may invalidate the subsequent causal analysis. Moreover, the computation and inference are challenging...
