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作者：Krueger, AB; Zhu, P
作者单位：Princeton University
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作者：Greenland, S
作者单位：University of California System; University of California Los Angeles; University of California System; University of California Los Angeles
摘要：This article examines the potential for misleading inferences from conventional analyses and sensitivity analyses of observational data, and describes some proposed solutions based on specifying prior distributions for uncontrolled sources of bias. The issues are illustrated in a sensitivity analysis of confounding in a study of residential wire code and childhood leukemia and in a pooled analysis of 12 studies of magnetic-field measurements and childhood leukemia. Both analyses have been inte...
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作者：Rosenthal, JS
作者单位：University of Toronto
摘要：This article considers nearly-periodic Markov chains that may have excellent functional estimation properties but poor distributional convergence rate. It shows how simple modifications of the chain (involving using a random number of iterations) can greatly improve the distributional convergence of the chain. Various theoretical results about convergence rates of the modified chains are proven. A number of examples, including a transdimensional Markov chain Monte Carlo example, a card-shuffli...
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作者：Gilbert, S
作者单位：Southern Illinois University System; Southern Illinois University
摘要：In one-way analysis of variance, a main interest is in differences among the groups that comprise the population. For a given parameter, such as a mean value, data yield parameter estimates for each group, as well as group rankings based on these statistics. Here ranking probabilities are studied under the assumption that parameter estimates are well approximated by a normal distribution, either in finite samples or asymptotically, with possible intergroup heteroscedasticity and correlation. P...
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作者：Clements, A; Hurn, S; Lindsay, K
作者单位：Queensland University of Technology (QUT); University of Glasgow
摘要：It is well known that the manipulation of sample data by means of a parametric function can improve the performance of kernel density estimation. This article proposes a two-parameter Mobius-like function to map sample data drawn from a semi-infinite space into [-1, 1). A standard kernel method is then used to estimate the density. The proposed method is shown to yield effective estimates of density and is computationally more efficient than other well-known transformation methods. The efficac...
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作者：Hjort, NL; Claeskens, G
作者单位：University of Oslo; Texas A&M University System; Texas A&M University College Station
摘要：The traditional use of model selection methods in practice is to proceed as if the final selected model had been chosen in advance, without acknowledging the additional uncertainty introduced by model selection. This often means underreporting of variability and too optimistic confidence intervals. We build a general large-sample likelihood apparatus in which limiting distributions and risk properties of estimators post-selection as well as of model average estimators are precisely described, ...
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作者：Bühlmann, P; Yu, B
作者单位：Swiss Federal Institutes of Technology Domain; ETH Zurich; University of California System; University of California Berkeley
摘要：This article investigates a computationally simple variant of boosting, L(2)Boost, which is constructed from a functional gradient descent algorithm with the L-2-loss function. Like other boosting algorithms, L(2)Boost uses many times in an iterative fashion a prechosen fitting method, called the learner. Based on the explicit expression of refitting of residuals of L(2)Boost, the case with (symmetric) linear learners is studied in detail in both regression and classification. In particular, w...
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作者：Dunson, DB; Colombo, B
作者单位：National Institutes of Health (NIH) - USA; NIH National Institute of Environmental Health Sciences (NIEHS); University of Padua
摘要：Cervical mucus hydration increases during the fertile interval before ovulation. Because sperm. can only penetrate mucus having a high water content, cervical secretions provide a reliable marker of the fertile days of the menstrual cycle. This article develops a Bayesian approach for modeling of daily observations of cervical mucus and applies the approach to assess heterogeneity among women and cycles from a given woman with respect to the increase in mucus hydration during the fertile inter...
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作者：Gupta, M; Liu, JS
作者单位：Harvard University
摘要：Detection of unknown patterns from a randomly generated sequence of observations is a problem arising in fields ranging from signal processing to computational biology. Here we focus on the discovery of short recurring patterns (called motifs) in DNA sequences that represent binding sites for certain proteins in the process of gene regulation. What makes this a difficult problem is that these patterns can vary stochastically. We describe a novel data augmentation strategy for detecting such pa...
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作者：Portnoy, S
作者单位：University of Illinois System; University of Illinois Urbana-Champaign
摘要：Using quantile regression to analyze survival times offers an valuable complement to traditional Cox proportional hazards modelling. Unfortunately, this approach has been hampered by the lack of a conditional quantile estimator for censored data that is directly analogous to the Kaplan-Meier estimator and applies under standard assumptions for censored regression models. Here a recursively reweighted estimator of the regression quantile process is developed as a direct generalization of the Ka...
