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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：XIE, Y; PIMENTEL, EF
摘要：This article revises the Coale-Trussell method for analyzing data from the World Fertility Survey by proposing and testing alternative log-linear and log-multiplicative models. The models, in one form or another, represent the structural constraint underlying the Coale-Trussell method on the variation in the age pattern of human fertility. With a Poisson distribution assumption for the number of births, several parameters of the models are simultaneously estimated via maximum likelihood. It is...
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作者：HART, JD; WEHRLY, TE
摘要：It is well known that kernel regression estimators are subject to so-called boundary or edge effects, a phenomenon in which the bias of an estimator increases near the endpoints of the estimation interval. When the regression curve is linear or nearly linear, the requisite amount of smoothing is so great that the boundary region is effectively the entire estimation interval. Special boundary kernels are proposed here to deal with such cases. It is shown that the proposed kernel estimator has a...
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作者：GU, C
作者单位：University of British Columbia
摘要：Recent developments of multivariate smoothing methods provide a rich collection of feasible models for nonparametric multivariate data analysis. Among the most interpretable are models with additive terms. Construction of various models and algorithms for computing the models have been the main concern of the existing literature in this area. Few results are available on the validation of computed fits, and many applications of nonparametric methods unfortunately end up interpreting the noise....
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作者：MULLER, KE; LAVANGE, LM; RAMEY, SL; RAMEY, CT
作者单位：Research Triangle Institute; University of North Carolina; University of North Carolina Chapel Hill; University of North Carolina; University of North Carolina Chapel Hill; University of Alabama System; University of Alabama Birmingham
摘要：Recently developed methods for power analysis expand the options available for study design. We demonstrate methods can be applied by (1) reviewing their formulation and (2) describing their application in the preparation of a particular grant proposal. The focus is a complex but ubiquitous setting: repeated measures in a longitudinal study. Describing the development of the research proposal allows demonstrating the steps needed to conduct an effective power analysis. Discussion of the exampl...
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作者：AZARI, AS; MULLER, HG
摘要：We propose a multivariate smoothing method based on products of localized orthogonal polynomial series estimators for a smooth regression surface in the fixed-design regression model. The estimation of partial derivatives is included. The proposed method provides for automatic and efficient boundary modifications near the edges of the surface, assuming that the boundary of the support of the regression function satisfies some regularity conditions. By allowing for a preaveraging step, the corr...
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作者：GWET, JP; RIVEST, LP
作者单位：Laval University
摘要：Many techniques have been suggested to lower the impact of outliers on sample survey estimates. Outliers can be downweighted by winsorization; that is, by replacing extreme data points by a data-dependent or a predetermined value before calculating estimates. Another approach is to reduce the weight of outliers, from the inverse sampling fraction to 1, in the estimation of population characteristics. In this article the problem of estimating the population mean using auxiliary information in t...
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作者：CARROLL, RJ; LI, KC
作者单位：Texas A&M University System; Texas A&M University College Station
摘要：A general nonlinear regression problem is considered with measurement error in the predictors. We assume that the response is related to an unknown linear combination of a multidimensional predictor through an unknown link function. Instead of observing the predictor, we instead observe a surrogate with the property that its expectation is linearly related to the true predictor with constant variance. We identify an important transformation of the surrogate variable. Using this transformed var...
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作者：LITTLE, RJA
摘要：The literature of regression analysis with missing values of the independent variables is reviewed. Six classes of procedures are distinguished: complete case analysis, available case methods, least squares on imputed data, maximum likelihood, Bayesian methods, and multiple imputation. Methods are compared and illustrated when missing data are confined to one independent variable, and extensions to more general patterns are indicated. Attention is paid to the performance of methods when the mi...
