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有限总体中类别数量的估计AI 解读

We use an extension of the generalized jackknife approach of Gray and Schucany to obtain new nonparametric estimators for the number of classes in a finite population of known size. We also show that generalized jackknife estimators are closely related to certain Horvitz–Thompson estimators, to an estimator of Shlosser, and to estimators based on sample coverage. In particular, the generalized jackknife approach leads to a modification of Shlosser's estimator that does not…

混合采样方法综述AI 解读

A composite is formed by collecting multiple sample units and combining them in their entirety or in part, to form a new sample. The sample units that make up the composite may retain their integrity or be homogenized through physical processes such as ball milling, sieving, shaking, or centrifuging. One or more subsequent measurements are taken on the composite and the information on the sample units is lost. This counterintuitive loss of information has fueled opposition…

多元门限模型的检验与建模AI 解读

Threshold autoregressive models in which the process is piecewise linear in the threshold space have received much attention in recent years. In this article I use predictive residuals to construct a test statistic for detecting threshold nonlinearity in a vector time series and propose a procedure for building a multivariate threshold model. The thresholds and the model are selected jointly based on the Akaike information criterion. The finite-sample performance of the…

多元失效时间数据的边际回归模型AI 解读

In this article we propose a general Cox-type regression model to formulate the marginal distributions of multivariate failure time data. This model has a nested structure in that it allows different baseline hazard functions among distinct failure types and imposes a common baseline hazard function on the failure times of the same type. We prove that the maximum “quasi-partial-likelihood” estimator for the vector of regression parameters under the independence working…

固定行边际总数的 k×l 列联表同质性非参数贝叶斯分析AI 解读

In this work I postulate a nonparametric Bayesian model for data that can be accommodated in a contingency table with fixed right margin totals. This data structure usually arises when comparing different groups regarding classification probabilities for a number of categories. I assume that cell count vectors for each group are conditionally independent, with multinomial distribution given vectors of classification probabilities. In turn, these vectors of probabilities are…

使用狄利克雷过程先验的贝叶斯多重比较AI 解读

We consider the problem of multiple comparisons from a Bayesian viewpoint. The family of Dirichlet process priors is applied in the form of baseline prior/likelihood combinations to obtain posterior probabilities for various hypotheses of equality among population means. The baseline prior/likelihood combinations considered here are beta/binomial and normal/inverted gamma with equal variances on treatment means. The prior probabilities of the hypotheses depend directly on…

二元空间数据的复合似然方法AI 解读

Conventional geostatistics addresses the problem of estimation and prediction for continuous observations. But in many practical applications in public health, environmental remediation, or ecological research the most commonly available data are in the form of counts (e.g., number of cases) or indicator variables denoting above or below threshold values. Also, in many situations it is less expensive to obtain an imprecise categorical observation than to obtain precise…

两种参数化多项超额变异模型的大簇结果AI 解读

Two parametric extra variation models are considered. Approximate closed-form expressions are given for the Fisher information matrices. The expressions are useful in computing maximum likelihood estimates and obtaining large cluster efficiencies. A simulation study shows that the approximations perform very well even in clusters of moderate size. The models are applied in illustrative examples. A goodness-of-fit test is developed that is applicable even when the cluster…

通过再生实现自适应马尔可夫链蒙特卡洛AI 解读

Markov chain Monte Carlo (MCMC) is used for evaluating expectations of functions of interest under a target distribution π. This is done by calculating averages over the sample path of a Markov chain having π as its stationary distribution. For computational efficiency, the Markov chain should be rapidly mixing. This sometimes can be achieved only by careful design of the transition kernel of the chain, on the basis of a detailed preliminary exploratory analysis of π. An…

模式识别中的相关性与高维一致性AI 解读

Classical discriminant analysis breaks down when the feature vectors are of extremely high dimension; for example, when the basic observation is a random function observed over a fine grid. Alternative methods have been developed assuming a simplified form for the covariance structure. We analyze the high-dimensional asymptotics of some of these methods, emphasizing the effects of correlations such as occur when the baseline is random. For instance, the Euclidean distance…

嵌套与交叉曲线样本分析的平滑样条模型AI 解读

We introduce a class of models for an additive decomposition of groups of curves stratified by crossed and nested factors, generalizing smoothing splines to such samples by associating them with a corresponding mixed-effects model. The models are also useful for imputation of missing data and exploratory analysis of variance. We prove that the best linear unbiased predictors (BLUPs) from the extended mixed-effects model correspond to solutions of a generalized penalized…

完全接受或完全拒绝依从下的随机试验生存分析：癌症筛查成本效果估计AI 解读

Many randomized cancer screening trials involve all-or-none compliance. Some subjects randomized to an offer of screening refuse screening, and some subjects randomized to no offer of screening obtain screening outside the trial. The primary analysis to test whether or not cancer screening reduces cancer mortality is by intent-to-treat. To estimate the cost-effectiveness of screening, it is necessary to adjust for all-or-none compliance. Heretofore, adjustments for…

不完美参照检验下相关诊断检验的灵敏度与特异度评估AI 解读

The purpose of a diagnostic efficacy study is to evaluate and compare the sensitivities and specificities of several diagnostic tests. Usually the diagnostic tests are correlated conditional on disease status, and the reference test is subject to error. In the Chlamydia trachomatis study, five screening tests for detecting chlamydia in endocervical specimens were compared. The five tests are correlated, and the reference test (the cell culture test) has less than 100%…

计算机化自适应测试中异常作答者的贝叶斯识别AI 解读

We consider the problem of identifying examinees with aberrant response patterns in a computerized adaptive test (CAT). The vector Y of responses of an examinee from a CAT is a multivariate response vector. Multivariate observations may be outlying in many different directions, and we characterize specific directions as corresponding to outliers with different interpretations. We develop a class of outlier statistics to identify different types of outliers based on a control…

价格与税制改革的参数和非参数分析方法AI 解读

In many public policy problems, we need to estimate the way in which policy changes affect people's behavior. In the analysis of tax and subsidy reform—the topic of this article—we need to know how tax-induced price changes affect the amounts that people buy of the taxed goods. We present various economic and statistical approaches to obtaining the required estimates. We consider the standard structural methods in economics, where the behavior and welfare of individual…

定向项目布点与坦桑尼亚计划生育项目效果估计AI 解读

Most studies evaluating the impact of family planning on fertility treat the presence of family planning clinics as being “randomly” assigned among the areas included in the study. They tend to ignore the possibility that the distribution of services may be related to the fertility level observed in a particular area. In some cases the distribution of services may respond to a conscious effort by public authorities or funding agencies to target areas with observed higher…

未提问与未回答：多项调查的多重插补AI 解读

We present a method of analyzing a series of independent cross-sectional surveys in which some questions are not answered in some surveys and some respondents do not answer some of the questions posed. The method is also applicable to a single survey in which different questions are asked or different sampling methods are used in different strata or clusters. Our method involves multiply imputing the missing items and questions by adding to existing methods of imputation…

广义线性模型中遗漏协变量与估计效率AI 解读

Although omitting covariates associated with the response in generalized linear models can yield seriously biased estimates of the effects of the included covariates, in certain settings there is no bias. This article considers the effect of omitted covariates on the efficiency of the estimated effects of the included covariates in these cases. I consider the case where the omitted covariate is independent of the included covariates, as in studies with randomized treatment…

非参数随机序关系的统一似然推断方法AI 解读

For data in a two-way contingency table with ordered margins, we consider various hypotheses of stochastic orders among the conditional distributions considered by rows and show that each is equivalent to requiring that an invertible transformation of the vectors of conditional row probabilities satisfies an appropriate set of linear inequalities. This leads to the construction of a general algorithm for maximum likelihood estimation under multinomial sampling and provides a…

一般回归问题中线性成分数量的检验AI 解读

This article presents a method for testing the dimension of a general regression model without assuming any specific model for the distribution of the regressors. Examples of application and comparisons with existing methods are also studied.

方向数据的投影多元线性模型AI 解读

We introduce the spherically projected multivariate linear model for directional data. This model treats directional observations as projections onto the unit sphere of unobserved responses from a multivariate linear model. Focusing on the important case of circular data, we show that maximum likelihood estimates for the model are readily computed using iterative methods, in sharp contrast with competing approaches. Examples are given to demonstrate the resulting methodology…

连续状态空间马尔可夫链的离散化与 MCMC 收敛评估AI 解读

We show that continuous state-space Markov chains can be rigorously discretized into finite Markov chains. The idea is to subsample the continuous chain at renewal times related to small sets that control the discretization. Once a finite Markov chain is derived from the Markov chain Monte Carlo output, general convergence properties on finite state spaces can be exploited for convergence assessment in several directions. Our choice is based on a divergence criterion derived…