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作者：Neocleous, Tereza; Vanden Branden, Karlien; Portnoy, Stephen
作者单位：University of Illinois System; University of Illinois Urbana-Champaign; KU Leuven
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作者：Shen, Xiaotong; Huang, Hsin-Cheng
作者单位：University of Minnesota System; University of Minnesota Twin Cities; Academia Sinica - Taiwan
摘要：Central to statistical theory and application is statistical modeling, which typically involves choosing a single model or combining a number of models of different sizes and from different sources. Whereas model selection seeks a single best modeling procedure, model combination combines the strength of different modeling procedures. In this article we look at several key issues and argue that model assessment is the key to model selection and combination. Most important, we introduce a gener...
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作者：Hitchcock, DB; Casella, G; Booth, JG
作者单位：University of South Carolina System; University of South Carolina Columbia; State University System of Florida; University of Florida; Cornell University
摘要：We examine the effect of presmoothing functional data oil estimating the dissimilarities among objects in a dataset, with applications to cluster analysis and other distance methods, such as multidimensional scaling and statistical matching. We prove that a shrinkage method of smoothing results in a better estimator of the dissimilarities among a set of noisy curves. For a model with independent noise structure, the smoothed-data dissimilarity estimator dominates the observed-data estimator. F...
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作者：Akritas, Michael G.; Antoniou, Efi S.; Kuha, Jouni
作者单位：Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; University of London; London School Economics & Political Science; University of London; London School Economics & Political Science
摘要：We propose a nonparametric approach to the analysis of factorial designs where each subject is observed at two time points and both observations are subject to missingness. The procedures are fully nonparametric in that they do not require continuity, and do not impose models to describe the relation of the response distribution in different factor-level combinations. The approach for estimating and testing treatment and time effects is based on a method, which we introduce, for estimating a d...
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作者：De Santis, F
作者单位：Sapienza University Rome
摘要：This article considers a robust Bayesian approach to the sample size determination problem. We focus on global Bayesian robustness that studies lower bound (L-n), upper bound (U-n), and range (R-n) of posterior quantities of interest. obtained as the prior varies in a class of distributions. Specifically, we are interested in the selection of an appropriate sample size that gives guarantees to the researcher of observing a small value of the range and, depending on the problems, either a suffi...
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作者：Morris, Jeffrey S.; Arroyo, Cassandra; Coull, Brent A.; Ryan, Louise M.; Herrick, Richard; Gortmaker, Steven L.
作者单位：University of Texas System; UTMD Anderson Cancer Center; Morehouse School of Medicine; Harvard University; Harvard T.H. Chan School of Public Health; Harvard University; Harvard T.H. Chan School of Public Health
摘要：We present a case study illustrating the challenges of analyzing accelerometer data taken from a sample of children participating in an intervention study designed to increase physical activity. An accelerometer is a small device worn on the hip that records the minute-by-minute activity levels throughout the day for each day it is worn. The resulting data are irregular functions characterized by many peaks representing short bursts of intense activity. We model these data using the wavelet-ba...
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作者：Tan, Zhiqiang
作者单位：Johns Hopkins University; Johns Hopkins Bloomberg School of Public Health
摘要：Recent researches in econometrics and statistics have gained considerable insights into the use of instrumental variables (lVs) for causal inference. A basic idea is that IVs serve as an experimental handle, the turning of which may change each individual's treatment status and, through and only through this effect, also change observed outcome. The average difference in observed outcome relative to that in treatment status gives the average treatment effect for those whose treatment status is...
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作者：Chen, Xiaohong; Fan, Yanqin; Tsyrennikov, Viktor
作者单位：New York University; Vanderbilt University
摘要：We propose a sieve maximum likelihood estimation procedure for a broad class of semiparametric multivariate distributions. A joint distribution in this class is characterized by a parametric copula function evaluated at nonparametric marginal distributions. This class of distributions has gained popularity in diverse fields due to its flexibility in separately modeling the dependence structure and the marginal behaviors of a multivariate random variable, and its circumvention of the curse of d...
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作者：Hafner, Christian M.; Linton, Oliver B.
作者单位：University of London; London School Economics & Political Science
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作者：Ho, Daniel E.; Imai, Kosuke
作者单位：Stanford University; Princeton University
摘要：Since the 2000 U.S. Presidential election, social scientists have rediscovered a long tradition of research examining the effects of ballot format on voting. Using a new dataset collected by The New York Times, we investigate the causal effect of being listed on the first ballot page in the 2003 California gubernatorial recall election. California law mandates a unique randomization procedure of ballot order that, when appropriately modeled, can be used to approximate a classical randomized ex...
