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放射治疗中剂量与局部肿瘤控制的建模AI 解读

We discuss models for predicting local control (prevention of tumor recurrence) after therapeutic radiation in cancer patients. The probability of control is first formulated from theoretical precepts. Biophysical principles dictate that the three factors in therapy that most universally influence outcome are total dose, number of sessions in which the dose is administered, and total time under treatment. We show that these principles also suggest the scale, or link…

随机样本量下比例参数的极小极大估计AI 解读

We study the problem of how to estimate the parameters of a multivariate hypergeometric distribution when the sample size n is assumed to be an ancillary statistic. The minimax estimator for squared error loss is given. This estimator differs from the well-known minimax estimator for fixed n. Furthermore, that classical estimator is shown to be not even admissible when n is random.

有限样本崩溃点的替代定义及其回归估计应用AI 解读

We propose an alternative definition of the finite-sample breakdown point. This breakdown point is invariant with respect to reparameterization and compatible with the Donoho-Huber breakdown point in linear regression situations. It also overcomes certain limitations of the definition proposed by Stromberg and Ruppert and can be used in a wide range of estimation problems. We investigate the breakdown properties of some nonlinear regression estimators. These results alert us…

利用准残差比较回归曲线AI 解读

We consider testing the equality of two regression functions using two independent samples. Three tests are proposed that are free of the restriction of having the same covariate values or sample sizes for both samples. Asymptotic distributions are given and results from a simulation study are presented that show the superior power properties of these tests over a competing test in a variety of cases, including the testing of hypotheses involving high-frequency curves when…

协变量存在测量误差的匹配病例对照研究中优势比回归参数的估计AI 解读

This article studies estimators of the odds ratio and odds ratio regression parameters in finely matched case-control studies containing a binary exposure of primary interest and subject-specific covariates that are subject to measurement error. A retrospective logistic regression model for the binary exposure variable is used. The effect of measurement errors on the conditional maximum likelihood estimator is determined. Three alternatives are considered: bias-corrected,…

Gumbel 吸引域中最大 k 个次序统计量的选择AI 解读

Statistical modeling of the largest k observations or the exceedances over a high threshold based on extreme value theory has produced powerful methods for drawing inferences about the tail behavior of a distribution; however, a method for selecting k has not been established. We suggest using a forward selection procedure based on a suitable goodness-of-fit statistic to search for the optimal k when the sample is of finite size and from a distribution in the domain of…

寿命数据建模及其疲劳模型应用AI 解读

A new model for the analysis of lifetime data in the presence of a covariate is derived based on physical and statistical considerations. The model depends on five parameters that have clear physical interpretations. Two methods for the estimation of the parameters and of the quantiles are presented: one based on the order statistics and the other a regression estimator. The quantile estimators as well as the estimators of four of the five parameters are given in closed…

两样本问题中似然比序的统计推断AI 解读

We obtain the maximum likelihood estimators of two multinomial probability vectors under the constraint that they are likelihood ratio ordered. We extend this estimation approach to the case of two univariate distributions and show strong consistency of the estimators. We also derive and study the asymptotic distribution of the likelihood ratio statistic for testing the equality of two discrete probability distributions against the alternative that one distribution is…

随机截断数据下概率的非参数似然比区间估计AI 解读

We consider the problem of interval estimation of probabilities for randomly truncated data. The best-known method is based on the normal approximation of the product-limit estimator and has a drawback that it may produce intervals containing impossible values outside the range [0, 1]. Its small-sample performance is also not satisfactory. In this article we investigate an alternative approach that derives confidence intervals directly from a conditional nonparametric…

基于典型相关分析的协整检验AI 解读

Critical values are provided for four new tests for cointegration based on the canonical correlations and variates of a development of the Box-Tiao procedure. It is found that in finite samples the power of three of these tests, unlike the power of Johansen's and Engle and Yoo's tests, is highly robust to the correlation between the disturbances in the cointegrating relationships and those generating the common trends. The proposed tests perform well against these…

卫星臭氧数据的建模AI 解读

Starting in the early 1970s, the decline in column ozone over much of the earth has received much attention. Satellite ozone data, with the advantage of global coverage, now play an important role in assessing long-term trends in ozone distributions. We consider a class of space-time regression models for the analysis of satellite data on a fixed latitude, which take into account temporal and longitudinal dependence of the observations. The models can be used to test the…

基于条件期望的多元正态矩形区域概率近似AI 解读

Two new approximations for multivariate normal probabilities for rectangular regions, based on conditional expectations and regression with binary variables, are proposed. One is a second-order approximation that is much more accurate but also more numerically time-consuming than the first-order approximation. A third approximation, based on the moment-generating function of a truncated multivariate normal distribution, is proposed for orthant probabilities only. Its…

线性判别分析中的诊断AI 解读

Some new diagnostic measures in discriminant analysis are proposed. They can be expressed in terms of the two fundamental influence statistics in discriminant analysis: d i 2 and ψ i . A theorem on the asymptotic distributions of the fundamental statistics is derived. Based on the theorem, the proposed measures can be shown to be asymptotically distributed as functions of independent chi-squared and standard normal random variables. Critical values and expected quantiles of…

多元数据变换中的诊断与稳健估计AI 解读

This article presents a method for detecting multivariate outliers that might be distorting the estimation of a transformation to normality. It also proposes a robust estimator of the transformation parameter.

Gibbs 抽样器的收敛判据AI 解读

This article presents new operational convergence criteria for the Gibbs sampler (GS) and related procedures that are useful for determining whether they not only have converged but also have converged to provide reliable results. Three GS convergence criteria are presented and applied: the difference convergence criterion (DC2), the ratio convergence criterion (RC2), and the anchored ratio convergence criterion (ARC2). Their uses and properties are discussed and examples…

退火式马尔可夫链蒙特卡洛及其祖先推断应用AI 解读

Markov chain Monte Carlo (MCMC; the Metropolis-Hastings algorithm) has been used for many statistical problems, including Bayesian inference, likelihood inference, and tests of significance. Though the method generally works well, doubts about convergence often remain. Here we propose MCMC methods distantly related to simulated annealing. Our samplers mix rapidly enough to be usable for problems in which other methods would require eons of computing time. They simulate…

最优置信集合、生物等效性与帕斯卡蜗线AI 解读

We begin with a decision-theoretic investigation into confidence sets that minimize expected volume at a given parameter value. Such sets are constructed by inverting a family of uniformly most powerful tests, and hence they also enjoy the optimality property of being uniformly most accurate. In addition, these sets possess Bayesian optimal volume properties and represent the first case (to our knowledge) of a frequentist 1 – α confidence set that possesses a Bayesian…

分析可交换二元数据的饱和模型：临床与发育毒性研究应用AI 解读

Correlated binary data occur very frequently in statistical practice. In many applications, it is reasonable to assume that data from the same cluster are exchangeable. Such data are commonly encountered in cluster sample surveys, teratological experiments, ophthalmologic and otolaryngologic studies, and other clinical trials. The standard methods of analyzing these data include the use of beta-binomial models and generalized estimating equations with third and fourth…

生殖与发育实验中联合暴露数据的阈值模型AI 解读

In risk assessment, thresholds are generally believed to exist for toxic reproductive and developmental agents. Therefore, dose combinations exist below the threshold where the response is not distinguishable from background and above the threshold where a dose-response trend results. Because data from combination experiments are more reflective of human exposure to environmental agents, threshold models that incorporate the effect of interactions among these agents are…

基于 DNA 图谱的法医识别中的参数乘积估计AI 解读

In many areas, such as reliability and forensic identification, it is of interest to estimate a product of unknown parameters, each of which is estimated from test data. The maximum likelihood estimator usually used in both applications is approximately unbiased but has an asymmetric sampling distribution, particularly when the sample size is not large. Consequently, most estimates understate the parameter value, often substantially, and this may be a serious drawback if…

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