2004

最新文章

• Exact and approximate inferences for nonlinear mixed-effects models with missing covariates AI翻译
  作者：Wu, L
  作者单位：University of British Columbia
  摘要：Nonlinear mixed-effects (NLME) models are popular in many longitudinal studies, including human immunodeficiency virus (HIV) viral dynamics, pharmacokinetic analyses, and studies of growth and decay. In practice, covariates in these studies often contain missing data, and so standard complete-data methods are not directly applicable. In this article we propose Monte Carlo parameter-expanded (PX)-EM algorithms for exact and approximate likelihood inferences for NLME models with missing covariat...
• Computational methods for multiplicative intensity models using weighted gamma processes: Proportional hazards, marked point processes, and panel count data AI翻译
  作者：Ishwaran, H; James, LF
  作者单位：Cleveland Clinic Foundation; Hong Kong University of Science & Technology
  摘要：We develop computational procedures for a class of Bayesian nonparametric and semiparametric multiplicative intensity models incorporating kernel mixtures of spatial weighted gamma measures. A key feature of our approach is that explicit expressions for posterior distributions of these models share many common structural features with the posterior distributions of Bayesian hierarchical models using the Dirichlet process. Using this fact, along with an approximation for the weighted gamma proc...
• A random pattern-mixture model for longitudinal data with dropouts AI翻译
  作者：Guo, WS; Ratcliffe, SJ; Ten Have, TT
  作者单位：University of Pennsylvania
  摘要：Pattern-mixture models are frequently used for longitudinal data analysis with dropouts because they do not require explicit specification Of the dropout mechanism. These models stratify the data according to time to dropout and formulate a model for each stratum. This usually results in underindentifiability, because we need to estimate many pattern-specific parameters even though the eventual interest is usually or, the marginal parameters. In this article we extend this framework to a rando...
• Testing homogeneity in a mixture distribution via the L2 distance between competing models AI翻译
  作者：Charnigo, R; Sun, JY
  作者单位：University of Kentucky; University of Kentucky; University System of Ohio; Case Western Reserve University
  摘要：Ascertaining the number of components in a mixture distribution is an interesting and challenging problem for statisticians. Chen, Chen. and Kalbfleisch recently proposed a modified likelihood ratio test (MLRT), which is distribution-free and locally most powerful, asymptotically. In this article we present a new method for testing whether a finite mixture distribution is homogeneous. Our method, the D test, is based on the L-2 distance between a fitted homogeneous model and a fitted heterogen...
• Methodology for evaluating a partially controlled longitudinal treatment using principal stratification, with application to a needle exchange program AI翻译
  作者：Frangakis, CE; Brookmeyer, RS; Varadhan, R; Safaeian, M; Vlahov, D; Strathdee, SA
  作者单位：Johns Hopkins University; Johns Hopkins Bloomberg School of Public Health; Johns Hopkins University; Johns Hopkins Bloomberg School of Public Health; New York Academy of Medicine
  摘要：We consider studies for evaluating the short-term effect of a treatment of interest on a time-to-event outcome. The studies we consider are partially controlled in the following sense: (I) Subjects' exposure to the treatment of interest can vary over time, but this exposure is not directly controlled by the study; (2) subjects' follow-up time is not directly controlled by the study; and (3) the study directly controls another factor that can affect subjects' exposure to the treatment of intere...
• Smooth and accurate multivariate confidence regions AI翻译
  作者：Yang, B; Kolassa, JE
  作者单位：Merck & Company; Schering Plough Corporation; Rutgers University System; Rutgers University New Brunswick
  摘要：This article describes multivariate approximate conditional confidence regions for canonical exponential families. These confidence regions have actual coverage probabilities that are closer to their nominal levels than are the actual coverage probabilities of traditional normal-theory regions and have boundaries that are smoother than those obtained by inverting traditional exact tests. Our method is based on constructing one-dimensional conditional tests, combining p values, and inverting. M...
• Large-scale simultaneous hypothesis testing: The choice of a null hypothesis AI翻译
  作者：Efron, B
  作者单位：Stanford University
  摘要：Current scientific techniques in genomics and image processing routinely produce hypothesis testing problems with hundreds or thousands of cases to consider simultaneously. This poses new difficulties for the statistician, but also opens new opportunities. In particular, it allows empirical estimation of an appropriate null hypothesis. The empirical null may be considerably more dispersed than the usual theoretical null distribution that would be used for any one case considered separately. An...
• Does the statistics profession have an identity crisis? AI翻译
  作者：Mason, RL
  作者单位：Southwest Research Institute
  摘要：The field of statistics has numerous areas of application and many positive attributes. Various companies and organizations around the world have chosen not only to adopt statistical tools, but also to integrate them into their associated work and ultimately into their decision making processes. Consequently, the value of statistics as a quantitative tool of importance to society appears to be continually increasing. In contrast, statisticians are less visible to society, and their importance ...
• Location-scale depth - Comment AI翻译
  作者：McCullagh, P
  作者单位：University of Chicago
• Location-scale depth - Comment AI翻译
  作者：Serfling, R
  作者单位：University of Texas System; University of Texas Dallas