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作者：Kvam, PH; Peña, EA
作者单位：University System of Georgia; Georgia Institute of Technology; University of South Carolina System; University of South Carolina Columbia
摘要：An estimator for the load-share parameters in an equal load-share model is derived based on observing k-component parallel systems of identical components that have a continuous distribution function F((.)) and failure rate r((.)). In an equal load-share model. after the first of k components fails, failure rates for the remaining components change from r(t) to gamma(1)r(t), then to gamma(2)r(t) after the next failure, and so on. On the basis of observations on n independent and identical syst...
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作者：Liao, JG; Qaqish, BF
作者单位：Rutgers University System; Rutgers University New Brunswick; Rutgers University Biomedical & Health Sciences; University of North Carolina; University of North Carolina Chapel Hill
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作者：Ruppert, D
作者单位：Cornell University
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作者：García-Escudero, LA; Gordaliza, A
作者单位：Universidad de Valladolid
摘要：The use of Mahalanobis distances has a long history in statistics. Given a sample of size n and general location and scatter estimators, m(n) and Sigma(n), we can define generalized radii as r(i)(n) = root(X-i-m(n))' Sigma(-1)(n) (X-i-m(n)). If we wish to trim observations based on the estimators m(n) and Sigma(n), then it is natural to first remove the most remote ones (i.e., those with the largest r(i)(n,)s). With this in mind, we define a process that maps the trimming proportion, alpha in ...
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作者：Maydeu-Olivares, A; Joe, H
作者单位：University of Barcelona; IE University; University of British Columbia
摘要：High-dimensional contingency tables tend to be sparse, and standard goodness-of-fit statistics such as X-2 cannot be used without pooling categories. As an improvement on arbitrary pooling, for goodness of fit of large 2(n) contingency tables, we propose classes of quadratic form statistics based on the residuals of margins or multivariate moments up to order r. These classes of test statistics are asymptotically chi-squared distributed under the null hypothesis. Further, the marginal residual...
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作者：Wang, CP; Brown, CH; Bandeen-Roche, K
作者单位：University of Texas System; University of Texas at San Antonio; State University System of Florida; University of South Florida; Johns Hopkins University
摘要：Growth mixture modeling has become a prominent tool for studying the heterogeneity of developmental trajectories within a population. In this article we develop graphical diagnostics to detect misspecification in growth mixture models regarding the number of growth classes, growth trajectory means, and covariance structures. For each model misspecification, we propose a different type of empirical Bayes residual to quantify the departure. Our procedure begins by imputing multiple independent s...
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作者：Merrick, JRW; Soyer, R; Mazzuchi, TA
作者单位：Virginia Commonwealth University; George Washington University; George Washington University
摘要：The Association of American Railroads wished to determine the effect of a maintenance practice known as grinding on the occurrence of rail fatigue defects and on the subsequent total traffic usage before a track must be replaced. Because a designed experiment was not practical, an analysis of historical data from the Canadian Northern Railroad is presented. In the analysis, certain covariate data are available, specifically the amount of grinding and some physical characteristics of the rail; ...
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作者：Shaffer, JP
作者单位：University of California System; University of California Berkeley
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作者：Machado, JAF; Silva, JMCS
作者单位：Universidade Nova de Lisboa; Universidade de Lisboa; Universidade de Lisboa
摘要：This article studies the estimation of conditional quantiles of counts. Given the discreteness of the data, some smoothness must be artificially imposed on the problem. We show that it is possible to smooth the data in a way that allows inference to be performed using standard quantile regression techniques. The performance and implementation of the estimators are illustrated by simulations and an application.
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作者：Sinha, S; Mukherjee, B; Ghosh, M; Mallick, BK; Carroll, RJ
作者单位：Texas A&M University System; Texas A&M University College Station; State University System of Florida; University of Florida
摘要：This article considers Bayesian analysis of matched case-control problems when one of the covariates is partially missing. Within the likelihood context, the standard approach to this problem is to posit a fully parametric model among the controls for the partially missing covariate as a function of the covariates in the model and the variables making up the strata. Sometimes the strata effects are ignored at this stage. Our approach differs not only in that it is Bayesian, but, far more impor...
