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作者：MARDEN, JI
摘要：A data set consisting of 143 rankings of 10 occupations from a survey of Goldberg has been analyzed in a number of recent papers. The purpose of this paper is to use so-called nested orthogonal contrasts of the occupations to gain further insight into the data. A contrast is a comparison of subsets of the occupations based on their relative ranks; contrasts are orthogonal if the comparisons they represent are not confounded. Various models based on sets of orthogonal contrasts-including contin...
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作者：YAMAGUCHI, K
作者单位：University of California System; University of California Los Angeles
摘要：Accelerated failure-time regression models with an additional regression model for the surviving fraction are proposed for the analysis of events that may never occur, regardless of censoring, for some people in the population risk set. The models attempt to estimate simultaneously the effects of covariates on the acceleration/deceleration of the timing of a given event and the surviving fraction; that is, the proportion of the population for which the event never occurs. The extended family o...
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作者：LANGE, N; CARLIN, BP; GELFAND, AE
作者单位：University of Minnesota System; University of Minnesota Twin Cities; University of Connecticut
摘要：Taking the absolute number of CD4 T-cells as a marker of disease progression for persons infected with the human immunodeficiency virus (HIV), we model longitudinal series of such counts for a sample of 327 subjects in the san Francisco Men's Health Study (Waves 1-8, excluding zidovudine cases). We conduct a fully Bayesian analysis of these data. We employ individual level nonlinear models incorporating such critical features as incomplete and unbalanced data, population covariates (age at stu...
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作者：ROCHON, J
作者单位：Western University (University of Western Ontario); University Western Ontario Hospital
摘要：Rochon and Helms (1989) presented a model for analyzing repeated measures experiments. The general linear model was used to assess the influence of covariate information, and ARMA time series models were put forward to characterize the covariance matrix among the repeated measures. Practical experience has suggested, however, that the ARMA assumption of constant variances and autocovariances over time is too restrictive for many applications. For example, observations may be relatively stable ...
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作者：GELFAND, AE; SMITH, AFM; LEE, TM
作者单位：Imperial College London
摘要：Constrained parameter problems arise in a wide variety of applications, including bioassay, actuarial graduation, ordinal categorical data, response surfaces, reliability development testing, and variance component models. Truncated data problems arise naturally in survival and failure time studies, ordinal data models, and categorical data studies aimed at uncovering underlying continuous distributions. In many applications both parameter constraints and data truncation are present. The stati...
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作者：BAGLIVO, J; OLIVIER, D; PAGANO, M
作者单位：Boston College; Harvard University; Harvard T.H. Chan School of Public Health; Harvard University; Harvard T.H. Chan School of Public Health; Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Dana-Farber Cancer Institute
摘要：Numerous goodness-of-fit tests with asymptotic chi-squared distributions have been proposed for discrete multivariate data, and there has been much discussion about using asymptotic results for computing critical values when there are small expected cell values. Although exact methods would be preferred in these situations, it generally is believed that such methods are computationally intractable. We propose methods for calculating exact distributions and significance levels for goodness-of-f...
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作者：LESAFFRE, E; KAUFMANN, H
摘要：The multivariate probit model (MPM) is a particular case of the class of correlated prediction models. A correlated prediction mode is especially useful when prediction or classification is envisaged into diagnostic classes that are combinations of binary responses. The parameter vector consists of a location part and an association part. The location part accounts for the effect the regressors have on the marginal probabilities of the binary responses. The association part corrects these prob...
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作者：GRAY, RJ
作者单位：Harvard University; Harvard T.H. Chan School of Public Health
摘要：In this article some flexible methods for modeling censored survival data using splines are applied to the problem of modeling the time to recurrence of breast cancer patients. The basic idea is to use fixed knot splines with a fairly modest number of knots to model aspects of the data, and then to use penalized partial likelihood to estimate the parameters of the model. Test statistics are proposed which are analogs of those used in traditional likelihood analysis, and approximations to the d...
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作者：KLEIN, R; PRESS, SJ
作者单位：University of California System; University of California Riverside
摘要：A two-dimensional scene is analyzed statistically by superimposing on it a rectangular grid and studying each square picture element (pixel) as one unit of the entire picture. With each pixel we want to associate one of K labels, but the label must be determined. Labels may be related to one another spatially, reflecting an underlying pattern in the scene. There is a noisy observation vector associated with each pixel, and these vectors are used contextually to classify the pixels; that is, to...
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作者：CRESSIE, N; HULTING, FL
作者单位：Alcoa
摘要：Growth models for tumors commonly are developed for a one-dimensional summary (e.g., number of cells, volume). At the supracellular level, however, ignoring tumor shape leads to oversimplification of the growth mechanism. For example, an oncologist would view the discovery of a compact tumor of volume v differently from the discovery of two osculatory compact tumors each of volume v/2. This article presents a growth model that uses shape information at a previous time to describe the tumor at ...
