排序方式: 共有11条查询结果,搜索用时 78 毫秒
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Westfall C 《Physician executive》2005,31(6):32-4, 36-7
Double-digit increases were seen in three physician executive positions and there are strong indications that the patient safety movement is impacting the way physician executives are paid. 相似文献
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Matthew Somerville Timothy Wilson Gary Koch Peter Westfall 《Pharmaceutical statistics》2005,4(1):7-13
We consider the problem of accounting for multiplicity for two correlated endpoints in the comparison of two treatments using weighted hypothesis tests. Various weighted testing procedures are reviewed, and a more powerful method (a variant of the weighted Simes test) is evaluated for the general bivariate normal case and for a particular clinical trial example. Results from these evaluations are summarized and indicate that the weighted methods perform in a manner similar to unweighted methods. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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We consider the multiple comparison problem where multiple outcomes are each compared among several different collections of groups in a multiple group setting. In this case there are several different types of hypotheses, with each specifying equality of the distributions of a single outcome over a different collection of groups. Each type of hypothesis requires a different permutational approach. We show that under a certain multivariate condition it is possible to use closure over all hypotheses, although intersection hypotheses are tested using Boole's inequality in conjunction with permutation distributions in some cases. Shortcut tests are then found so that the resulting testing procedure is easily performed. The error rate and power of the new method is compared to existing competitors through simulation of correlated data. An example is analyzed, consisting of multiple adverse events in a clinical trial. 相似文献
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Westfall C 《Physician executive》2007,33(6):14-6, 18-20, 22
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ABSTRACTIn statistical practice, inferences on standardized regression coefficients are often required, but complicated by the fact that they are nonlinear functions of the parameters, and thus standard textbook results are simply wrong. Within the frequentist domain, asymptotic delta methods can be used to construct confidence intervals of the standardized coefficients with proper coverage probabilities. Alternatively, Bayesian methods solve similar and other inferential problems by simulating data from the posterior distribution of the coefficients. In this paper, we present Bayesian procedures that provide comprehensive solutions for inferences on the standardized coefficients. Simple computing algorithms are developed to generate posterior samples with no autocorrelation and based on both noninformative improper and informative proper prior distributions. Simulation studies show that Bayesian credible intervals constructed by our approaches have comparable and even better statistical properties than their frequentist counterparts, particularly in the presence of collinearity. In addition, our approaches solve some meaningful inferential problems that are difficult if not impossible from the frequentist standpoint, including identifying joint rankings of multiple standardized coefficients and making optimal decisions concerning their sizes and comparisons. We illustrate applications of our approaches through examples and make sample R functions available for implementing our proposed methods. 相似文献
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Westfall James A. Nowak David J. Henning Jason G. Lister Tonya W. Edgar Christopher B. Majewsky Mark A. Sonti Nancy F. 《Urban Ecosystems》2020,23(4):905-917
Urban Ecosystems - Crown widths of woody plant species growing in urban areas are of considerable importance as an overall indicator of health and also serve as an important factor for assessing... 相似文献
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ABSTRACTWe develop new Bayesian regression tests for prespecified regression coefficients. Simple, closed forms of the Bayes factors are derived that depend only on the regression t-statistic and F-statistic and the usual associated t and F distributions. The priors that allow those forms are simple and also meaningful, requiring minimal but practically important subjective inputs. 相似文献