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含随机效应与测量误差的重复事件半参数回归AI 解读

Statistical methodology is presented for the regression analysis of multiple events in the presence of random effects and measurement error. Omitted covariates are modeled as random effects. Our approach to parameter estimation and significance testing is to start with a naive model of semiparametric Poisson process regression, and then to adjust for random effects and any possible covariate measurement error. We illustrate the techniques with data from a randomized clinical…

含随机效应与测量误差的重复事件半参数回归模型AI 解读

Statistical methodology is presented for the regression analysis of multiple events in the presence of random effects and measurement error. Omitted covariates are modeled as random effects. Our approach to parameter estimation and significance testing is to start with a naive model of semiparametric Poisson process regression, and then to adjust for random effects and any possible covariate measurement error. We illustrate the techniques with data from a randomized clinical…

受试者工作特征曲线的非参数与半参数估计AI 解读

The receiver operating characteristic (ROC) curve describes the performance of a diagnostic test used to discriminate between healthy and diseased individuals based on a variable measured on a continuous scale. The data consist of a training set of m responses $X_1, \dots, X_m$ from healthy individuals and n responses $Y_1, \dots, Y_n$ from diseased individuals. The responses are assumed i.i.d. from unknown distributions F and G, respectively. We consider estimation of the…

序贯 t、卡方与 F 检验的精确计算AI 解读

Sequential and group sequential procedures are proposed for monitoring repeated t, X2 or F statistics. These can be used to construct sequential hypothesis tests or repeated confidence intervals when the parameter of interest is a normal mean with unknown variance or a multivariate normal mean with variance matrix known or known up to a scale factor. Exact methods for calculating error probabilities and sample size distributions are described and tables of critical values…

中期分析：重复置信区间方法AI 解读

SUMMARY Most medical trials are monitored for early evidence of treatment differences or harmful side-effects and many sequential methods have been proposed for this. Similarly, data collected in a prospective epidemiological study are likely to be reviewed periodically in the course of the study. The repeated confidence interval approach, which combines aspects of sequential estimation and testing, allows a full exploration of the data at each interim analysis and does not…

We describe methods for the construction of a confidence interval for median survival time based on right-censored data. These methods are extended to the construction of repeated confidence intervals for the median, based on accumulating data; here, the overall probability that all intervals contain the true median is guaranteed at a fixed level. The use of repeated confidence intervals for median survival time in post-marketing surveillance is discussed.

中位生存时间的重复置信区间AI 解读

We describe methods for the construction of a confidence interval for median survival time based on right-censored data. These methods are extended to the construction of repeated confidence intervals for the median, based on accumulating data; here, the overall probability that all intervals contain the true median is guaranteed at a fixed level. The use of repeated confidence intervals for median survival time in post-marketing surveillance is discussed.

破坏性寿命试验的有效序贯设计及动物分批处死实验应用AI 解读

We consider the scheduling of inspection times in a life testing experiment when testing is destructive. One application is to animal carcinogenicity tests where it is desired to find serial sacrifice schedules which allow efficient estimation of the onset time distribution for a tumour which is assumed irreversible, nonlethal and occult, i.e. detectable only at death. A class of designs are introduced and their properties are discussed. It is shown how to construct a design…

破坏性寿命试验的高效序贯设计及动物分批处死实验应用AI 解读

We consider the scheduling of inspection times in a life testing experiment when testing is destructive. One application is to animal carcinogenicity tests where it is desired to find serial sacrifice schedules which allow efficient estimation of the onset time distribution for a tumour which is assumed irreversible, nonlethal and occult, i.e. detectable only at death. A class of designs are introduced and their properties are discussed. It is shown how to construct a design…

两臂老虎机问题中的优势比估计AI 解读

Asymptotically optimal sequential procedures are proposed for fixed width interval and for point estimation of the log odds ratio for two Bernoulli populations. The costs of observations can be different for the two populations and possibly dependent on the success probabilities. The interval estimation procedure is studied by simulation for two sampling cost structures of particular interest, namely when the goal is to minimize the total average sample size, and when the…

双臂指数临床试验中的序贯估计AI 解读

Asymptotically optimal sequential procedures are developed for point and interval estimation of the difference and ratio of the means of two exponential populations. This is done in a clinical trial setting in which the responses are exponentially distributed survival times and are subject to censoring. The usual situation in which observations are immediate is treated as a special case. Some simulation results are given for moderate sample sizes.

双臂老虎机问题中的优势比估计AI 解读

Asymptotically optimal sequential procedures are proposed for fixed width interval and for point estimation of the log odds ratio for two Bernoulli populations. The costs of observations can be different for the two populations and possibly dependent on the success probabilities. The interval estimation procedure is studied by simulation for two sampling cost structures of particular interest, namely when the goal is to minimize the total average sample size, and when the…

比较多个正态均值与指定标准的两种选择程序AI 解读

The problem of comparing k normal means with a specified (absolute) standard is considered. A single-stage and a two-stage (k + 1)-decision procedure are proposed for the cases of common known variance and common unknown variance, respectively. The procedures guarantee that (1) with probability at least P 0* (specified), no population is selected when the largest population mean is sufficiently less than the standard, and (2) with probability at least P 1* (specified), the…

任意分组、删失与截断数据的经验分布函数AI 解读

Summary This paper is concerned with the non-parametric estimation of a distribution function F, when the data are incomplete due to grouping, censoring and/or truncation. Using the idea of self-consistency, a simple algorithm is constructed and shown to converge monotonically to yield a maximum likelihood estimate of F. An application to hypothesis testing is indicated.

双侧删失数据下生存函数的非参数估计AI 解读

A simple iterative procedure is proposed for obtaining estimates of a response time distribution when some of the data are censored on the left and some on the right. The procedure is based on the product-limit method of Kaplan and Meier [15], and it also uses the idea of self-consistency due to Efron [8]. Under fairly general assumptions, the method is shown to yield unique consistent maximum likelihood estimators. Asymptotic expressions for their variances and covariances…

心脏移植数据的生存分析AI 解读

This article presents a number of parametric and nonparametric approaches to the analysis of nonexperimental heart transplant data from the Stanford Heart Transplantation Program, and attempts to come to some conclusion regarding whether heart transplantation is life-extending.