Biometrika

最新文章

• Direct estimation of the mean outcome on treatment when treatment assignment and discontinuation compete AI翻译
  作者：Lu, Xin; Johnson, Brent A.
  作者单位：Emory University; Rollins School Public Health; University of Rochester
  摘要：Several authors have investigated the challenges of statistical analyses and inference in the presence of early treatment termination, including a loss of efficiency in randomized controlled trials and a connection to dynamic regimes in observational studies. Popular estimation strategies for causal estimands in dynamic regimes lend themselves to studies where treatment is assigned at a finite number of points and the extension to continuous treatment assignment is nontrivial. We re-examine th...
• Diagnostic studies in sufficient dimension reduction AI翻译
  作者：Chen, Xin; Cook, R. Dennis; Zou, Changliang
  作者单位：National University of Singapore; University of Minnesota System; University of Minnesota Twin Cities; Nankai University
  摘要：Sufficient dimension reduction in regression aims to reduce the predictor dimension by replacing the original predictors with some set of linear combinations of them without loss of information. Numerous dimension reduction methods have been developed based on this paradigm. However, little effort has been devoted to diagnostic studies within the context of dimension reduction. In this paper we introduce methods to check goodness-of-fit for a given dimension reduction subspace. The key idea is...
• Benchmarked empirical Bayes methods in multiplicative area-level models with risk evaluation AI翻译
  作者：Ghosh, M.; Kubokawa, T.; Kawakubo, Y.
  作者单位：State University System of Florida; University of Florida; University of Tokyo; University of Tokyo
  摘要：The paper develops hierarchical empirical Bayes and benchmarked hierarchical empirical Bayes estimators of positive small area means under multiplicative models. The usual benchmarking requirement is that the small area estimates, when aggregated, should equal the direct estimates for the larger geographical areas. However, while estimating positive small area parameters, the conventional squared error or weighted squared error loss subject to the usual benchmark constraint may not produce pos...
• Maximum projection designs for computer experiments AI翻译
  作者：Joseph, V. Roshan; Gul, Evren; Ba, Shan
  作者单位：University System of Georgia; Georgia Institute of Technology; Procter & Gamble
  摘要：Space-filling properties are important in designing computer experiments. The traditional maximin and minimax distance designs consider only space-filling in the full-dimensional space; this can result in poor projections onto lower-dimensional spaces, which is undesirable when only a few factors are active. Restricting maximin distance design to the class of Latin hypercubes can improve one-dimensional projections but cannot guarantee good space-filling properties in larger subspaces. We prop...
• Adaptive randomized trial designs that cannot be dominated by any standard design at the same total sample size AI翻译
  作者：Rosenblum, Michael
  作者单位：Johns Hopkins University; Johns Hopkins Bloomberg School of Public Health
  摘要：Prior work has shown that the power of adaptive designs with rules for modifying the sample size can always be matched or improved by suitably chosen, standard, group sequential designs. A natural question is whether analogous results hold for other types of adaptive designs. We focus on adaptive enrichment designs, which involve preplanned rules for modifying enrollment criteria based on accrued data in a randomized trial. Such designs often involve multiple hypotheses, e.g., one for the tota...
• Jump information criterion for statistical inference in estimating discontinuous curves AI翻译
  作者：Xia, Zhiming; Qiu, Peihua
  作者单位：Northwest University Xi'an; State University System of Florida; University of Florida
  摘要：Nonparametric regression analysis when the regression function is discontinuous has many applications. Existing methods for estimating a discontinuous regression curve usually assume that the number of jumps in the regression curve is known beforehand, which is unrealistic in some situations. Although there has been research on estimation of a discontinuous regression curve when the number of jumps is unknown, the problem remains mostly open because such research often requires assumptions on ...
• Sieve maximum likelihood regression analysis of dependent current status data AI翻译
  作者：Ma, Ling; Hu, Tao; Sun, Jianguo
  作者单位：University of Missouri System; University of Missouri Columbia; Capital Normal University
  摘要：Current status data occur in contexts including demographic studies and tumorigenicity experiments. In such cases, each subject is observed only once and the failure time of interest is either left- or right-censored (Kalbfleisch & Prentice, 2002). Many methods have been developed for the analysis of such data (Huang, 1996; Sun, 2006), most of which assume that the failure time and the observation time are independent completely or given covariates. In this paper, we present a sieve maximum li...
• Designs for generalized linear models with random block effects via information matrix approximations AI翻译
  作者：Waite, T. W.; Woods, D. C.
  作者单位：University of Manchester; University of Southampton
  摘要：The selection of optimal designs for generalized linear mixed models is complicated by the fact that the Fisher information matrix, on which most optimality criteria depend, is computationally expensive to evaluate. We provide two novel approximations that reduce the computational cost of evaluating the information matrix by complete enumeration of response outcomes, or Monte Carlo approximations thereof: an asymptotic approximation that is accurate when there is strong dependence between obse...
• A Mobius transformation-induced distribution on the torus AI翻译
  作者：Kato, Shogo; Pewsey, Arthur
  作者单位：Research Organization of Information & Systems (ROIS); Institute of Statistical Mathematics (ISM) - Japan; Universidad de Extremadura
  摘要：We propose a five-parameter bivariate wrapped Cauchy distribution as a unimodal model for toroidal data. It is highly tractable, displays numerous desirable properties, including marginal and conditional distributions that are all wrapped Cauchy, and arises as an appealing submodel of a six-parameter distribution obtained by applying Mobius transformation to a pre-existing bivariate circular model. Method of moments and maximum likelihood estimation of its parameters are fast, and tests for in...
• Double-bootstrap methods that use a single double-bootstrap simulation AI翻译
  作者：Chang, Jinyuan; Hall, Peter
  作者单位：Southwestern University of Finance & Economics - China; University of Melbourne
  摘要：We show that, when the double bootstrap is used to improve performance of bootstrap methods for bias correction, techniques based on using a single double-bootstrap sample for each single-bootstrap sample can produce third-order accuracy for much less computational expense than is required by conventional double-bootstrap methods. However, this improved level of performance is not available for the single double-bootstrap methods that have been suggested to construct confidence intervals or di...