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精确Logistic回归的一种算法AI 解读

An efficient algorithm is given for the exact logistic analysis of a single parameter. Hypothesis tests and confidence intervals for a logistic regression parameter are obtained. The method provides for the control of the effect of a stratification factor when making inferences concerning the regression parameter.

不完整多元观测的两样本渐近分布无关检验AI 解读

Asymptotically distribution-free tests for equality of two multivariate distributions based on censored observations are proposed. By choosing appropriate test scores, we obtain the multivariate versions of the Gehan and log-rank tests. An important application of the proposed tests is in the area in which multiple observations are collected on study subjects, some of whom may have missing observations. The patterns of missing observations are allowed to differ for the two…

随机删失观测下比例风险模型的拟合优度检验AI 解读

A numerical omnibus test of fit for the two-sample proportional hazards model is proposed for randomly censored observations. The test is derived from Cox's partial likelihood and does not need a dummy time-dependent covariate or any partition of the time-axis. Consistency of the test is established. Examples are provided for illustration.

平滑先验与非线性回归AI 解读

Smoothness priors represent prior information that an unknown function does not change slope quickly and hence that the function describes a simple curve (e.g., Wahba 1978). In this article such priors for the multiple nonlinear regression model are developed in such a way that estimates and “standard errors” can be obtained as a natural and conceptually straightforward extension of linear multiple-regression estimation with the addition of dummy variables and dummy…

投影寻踪密度估计AI 解读

The projection pursuit methodology is applied to the multivariate density estimation problem. The resulting nonparametric procedure is often less biased than the kernel and near-neighbor methods. In addition, graphical information is produced that can be used to help gain geometric insight into the multivariate data distribution.

混合比例的最小距离与最大似然估计比较AI 解读

The estimation of mixing proportions in the mixture model is discussed, with emphasis on the mixture of two normal components with all five parameters unknown. Simulations are presented that compare minimum distance (MD) and maximum likelihood (ML) estimation of the parameters of this mixture-of-normals model. Some practical issues of implementation of these results are also discussed. Simulation results indicate that ML techniques are superior to MD when component…

样条回归平滑参数选择的快速交叉验证方法AI 解读

The spline smoothing approach to nonparametric regression is considered, with particular reference to the problem of choosing how much to smooth. Both computational and statistical aspects of the method of cross-validation are discussed. An approximate cross-validation method is proposed that requires a small linear amount of computer time. A simulation study indicates that the method has very good statistical properties. Some mathematical justification and motivation are…

观察性研究中的条件置换检验与倾向得分AI 解读

In observational studies, the distribution of treatment assignments is unknown, and therefore randomization tests are not generally applicable. However, permutation tests that condition on sample information about the treatment assignment mechanism can be applicable in observational studies, provided treatment assignment is strongly ignorable. These tests use the conditional distribution of the treatment assignments given a sufficient statistic for the unknown parameter of…

追踪1982年西班牙社会党胜选：贝叶斯分析AI 解读

An estimate of how people intended to vote was obtained four weeks before the Spanish general elections of October 1982. The evolution of opinion was followed during the campaign. Using a small sample of polling stations, the victory of the Spanish Socialist Party was predicted with great accuracy only two hours after the polls closed. A Bayesian hierarchical model was used.

具有特定结构的协方差矩阵求逆AI 解读

The inversion of a patterned covariance matrix is discussed. A general form of the correlation matrix is noted, and inversion by the method of tearing is applied. For certain correlation structures, the calculations are considerably simplified.

两阶段抽样中普通最小二乘方法的一则说明AI 解读

A class of linear models for two-stage sampling problems is considered. Ordinary least squares estimates are optimal for these models. For some parameters the usual least squares estimates of standard errors are shown to be appropriate.

非正交性对共用分母的 F 比率依赖关系的影响AI 解读

The problem of testing two or more hypotheses about cell means in an analysis of experimental data using F ratios sharing a common denominator mean squared error has been considered by Ghosh (1955), Ramachandran (1956), Krishnaiah (1964), and Hurlburt and Spiegel (1976). Hurlburt and Spiegel considered the case in which the numerator sums of squares of two F statistics are independent and the denominator sums of squares identical. In this article we extend Hurlburt and…

G谱估计量AI 解读

In this article a modified definition of the G-spectral estimator is given. It is shown that the resulting estimator is a method of moments autoregressive moving average (ARMA) spectral estimator that does not require an estimate of the moving average parameters. As a result, a new formula for the power spectrum of an ARMA process is given that does not explicitly involve the moving average (MA) parameters. This formula then leads to a closed-form expression for the MA…

随机序关系的似然比检验AI 解读

This article presents a method of extending the likelihood ratio principle to a nonparametric setting. The problem dealt with is a test for stochastic ordering. The resulting test is shown, via simulation, to have good power. It is shown to be consistent and unbiased.

完全区组分析中渐近分布无关方法的比较AI 解读

The Friedman test (or sign test when k = 2) depends entirely on within-block rankings. In a recent paper, Quade (1979) attempted to provide a test with more power than the Friedman test by considering a k-sample extension of the Wilcoxon signed ranks test. This is done by taking advantage of the between-block information. A third way to approach the problem and still retain both the within- and between-block information is first to transform all the observations to ranks…

秩与秩得分变换数据下双向设计的 F 统计量AI 解读

The limiting null distribution of the usual F statistic for main effects in the two-way layout is shown to have the same limiting distribution when applied to ranks and scores based on ranks as when applied to normal data. The limit is taken as the cell size N increases without bound. The denominator of the F statistic times (J − 1)/J is shown to provide an unbiased and consistent estimator of the limit (as N → ∞) of N -1 times the variance of the treatment sum of scores…

迁移者—留驻者模型的最大似然估计AI 解读

The discrete time mover-stayer model, a special mixture of two independent Markov chains, has been widely used in modeling the dynamics of social processes. The problem of maximum likelihood estimation of its parameters from the data, however, which consist of a sample of independent realizations of this process, has not been considered in the literature. I present a maximum likelihood procedure for the estimation of the parameters of the mover-stayer model and develop a…

小域估计中的设计一致性与模型依赖AI 解读

For small domains, we have a choice between design-consistent estimators that make the strongest possible use of auxiliary information and model-dependent design-biased alternatives such as the synthetic estimator. In this article, a design-consistent method is developed that borrows strength in the same way that the design-biased synthetic estimator does. The latter has a design-based mean squared error (MSE) advantage in small samples under the supposition that domains…

一种改进的稳健平滑方法AI 解读

Nonlinear data smoothers (filters) have the drawback that too many local peaks and troughs in a data sequence may be preserved. If Gaussian assumptions are not met, linear smoothers do not offer a desirable alternative. A refined method of smoothing out local peaks and troughs, while retaining the broad ones, is proposed. When used for signal recovery from data sequences contaminated with noise, this procedure, termed splicing, appears superior to other methods considered.…

回归模型的交叉验证AI 解读

A methodolgy for assessment of the predictive ability of regression models is presented. Attention is given to models obtained via subset selection procedures, which are extremely difficult to evaluate by standard techniques. Cross-validatory assessments of predictive ability are obtained and their use illustrated in examples.

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质量控制中的验收抽样AI 解读

Introduction Acceptance Quality Control Acceptance Control and Process Control Process Quality Control Background of Acceptance Quality Control NEW! Top 10 Reasons for Acceptance Sampling Probability and the Operating Characteristic Curve Probability Random Samples and Random Numbers Counting Possibilities Probability Calculus Operating Characteristic Curve Probability Functions Probability Distributions Measures of Distribution Functions Hypergeometric Distribution Binomial…

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