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作者：Zhang, D; Wells, MT; Turnbull, BW; Sparrow, D; Cassano, PA
作者单位：University of Rochester; Cornell University; Harvard University; Harvard University Medical Affiliates; US Department of Veterans Affairs; Veterans Health Administration (VHA); VA Boston Healthcare System; Boston University; Cornell University
摘要：There is continued debate regarding the exact relation between lower cholesterol levels and increased respiratory disease mortality. One of the goals of this study is to reveal the relationship between subcomponents of cholesterol and pulmonary function. We consider the subcomponents of total cholesterol, namely high-density lipoprotein cholesterol and low-density lipoprotein cholesterol, to investigate the relationship of cholesterol levels with pulmonary function in a longitudinal study. To ...
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作者：Kosorok, MR; Ma, SG
作者单位：University of Wisconsin System; University of Wisconsin Madison; University of Wisconsin System; University of Wisconsin Madison
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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：Tibshirani, R
作者单位：Stanford University; Stanford University
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作者：Zeng, DL; Yin, GS; Ibrahim, JG
作者单位：University of North Carolina; University of North Carolina Chapel Hill; University of Texas System; UTMD Anderson Cancer Center
摘要：A new class of transformed hazard rate models is considered that contains both the multiplicative hazards model and the additive hazards model as special cases. The sieve maximum likelihood estimators are derived for the model parameters, and the estimators for the regression coefficients are shown to be consistent and asymptotically normal with variance achieving the semiparametric efficiency bound. Simulation studies are conducted to examine the small-sample properties of the proposed estima...
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作者：Huang, J; Zhang, CH
作者单位：University of Iowa; University of Iowa; Rutgers University System; Rutgers University New Brunswick
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作者：Huang, J; Wang, D; Zhang, CH
作者单位：University of Iowa; University of Iowa; University of Alabama System; University of Alabama Birmingham; Rutgers University System; Rutgers University New Brunswick
摘要：A basic question in analyzing cDNA microarray data is normalization, the purpose of which is to remove systematic bias in the observed expression values by establishing a normalization curve across the whole dynamic range. A proper normalization procedure ensures that the normalized intensity ratios provide meaningful measures of relative expression levels. We propose a two-way semilinear model (TW-SLM) for normalization and analysis of microarray data. This method does not make the usual assu...
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作者：Wang, JPZ; Lindsay, BG
作者单位：Northwestern University; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park
摘要：We propose a class of penalized nonparametric maximum likelihood estimators (NPMLEs) for the species richness problem. We use a penalty term on the likelihood because likelihood estimators that lack it have an extreme instability problem. The estimators are constructed using a conditional likelihood that is simpler than the full likelihood. We show that the full-likelihood NPMLE solution given by Norris and Pollock can be found (with great accuracy) by using an appropriate penalty term on the ...
