失访和迄今存活病人的生存率

癌症临床工作的关键指标是生存率，尤其是那些失访和迄今存活病人即终检（也称删失）病例的生存率。后者尚无估计方法。本文提出生存率终检模型，利用该模型从整个样本生存率分离出终检病例生存率，并按二项分布理论构造其方差和置信限。其统计学意义是它揭示出生存率的终检成份和非终检成份，临床意义是它实现了对失访和迄今存活病人生存率的估计。与以往的笼统生存率估计相比，这显然提高了一步。附有工作实例描述其临床应用     

生存率终检模型

1引言．终检病人的生存经历是临床上最感兴趣的．通过建立观测到的和未观测到的生存经历之间的关系[1]可给出一个笼统的生存率估计，如kaplan－Meier[2]或Berkson－gage估计值．利用生存率终检模型[4]可给出终检病人生存专率；并经累积死亡数的分解得以实现．本文说明其原理并提出另外两种实现方法：Kanlan－Meier估计值的自相容性[5]和记分函数[6]．2．原理．令随机变量X是检验条件下的真正生存时间．其分布为F（t）＝P（XS心即病人到州的累积死亡概率，其补为F川一l一月（小令随机变量Y代表终检时间．其分布为E（t）＝P（y＜i）；其…     

广义非中心法

目的：本文提出一种广义非中心法以适应终检．它由经典非中心法衍变而来,用于多样本生存率检验所需样本量的测定．方法：其第１步继承经典方法。按已有的非中心卡方分布表和经典ｒ×２卡方统计量非中心参数表达式得出所需同源有效样本量;第２步由同源有效样本量在Ｗｅｉｂｕｌｌ生存分布下的参数表达式按预定终检率反推出所需样本量,并以逐个迭代实现样本量的分配．结果：与已有的校正终检样本量测定方法相比,该方法的特点是,与多样本生存率检验相匹配;摆脱了指数分布的假设;在无终检时还原为经典方法;其观测功效和预定功效精确吻合．结论：该方法可用于多样本癌症临床研究方案的设计．附有工作实例描述设计过程．     

两样本队列半数生存期检验:反射和检基统计量

依据反射或检基原理，本文提出用于截尾资料的两样本队列半数生存期（ＣＨＬ）检验．两样本合并ＣＨＬ经指数内插取自Ｋａｐｌａｎ－Ｍｅｉｅｒ或Ｂｅｒｋｓｏｎ－Ｇａｇｅ估计值．连续性校正，经以有效样本容量取代样本容量，扩展自Ｙａｔｅｓ校正．合并标准误来自同源性生存率方差估计值，后者经有效样本容量扩展自二项分布方差．无截尾时，这些统计量还原为经典中位数检验．与反射统计量相比，检基统计量具有更高的功效．附有工作实例描述其临床应用．     

均匀设计及其应用

均匀设计及其应用方开泰编者按：最近内刊上记者以标题“我国独创的“均匀设计”在国际领先，其社会经济效益不可估量”报导了均匀设计在飞航导弹及国民经济的应用及其潜在的重要作用，建议在我国采取计划推广与市场推广相结合的办法．本刊很高兴邀请均匀设计的发明人之一...     

临床试验(Ⅰ)

我们已经进入医学发展速度空前的新时代，新知识、新疗法、新的诊断工具与程序、新的预防措施层出不穷．这是由于科学的研究方法和传统的医学方法相结合而形成的．涉及人体的临床试验不仅因素复杂，而且常常面临伦理问题；但任何一种医学上的进展，最后都难免至少是部份地要依靠临床试验来证实． 本文的主要目的是向从事应用统计的读者介绍“临床试验”（ｃｌｉｎｉｃａｌ　Ｔｒｉａｌｓ）的地位与内涵；医学研究中的偏性；将试验设计与统计分析的基本原则与方法应用于临床医学研究遇到的问题、机会、进展和困难．具体内容分两篇．本篇包括：１，引言；２，医学研究中的偏性；３，伦理问题；４，试验设计，包括对传统方法的讨论、序贯平衡、不同阶段（Ｐｈｓｅ）相结合．下篇包括生存质量分析；依从性和Ｍｅｔａ分析等．     

拟蒙特卡罗方法用于估计多元回归函数

拟蒙特卡罗（QMC）方法被广泛用于解决数值分析和统计学中的各种问题，比如数值积分，最优化，试验设计，随机过程的模拟等．本文研究该方法在估计多元回归函数中的应用．证明了，在相当一般的条件下，均匀设计（或者，“代表点设计”）与回归函数傅里叶系数的QMC估计（对应地，使用拟随机重要性抽样的QMC估计）一起，构成一个回归函数的渐近最优投影估计．     

应用正交试验确定环已醇最佳工艺条件

应用正交试验确定环已醇最佳工艺条件．本文采用正交试验的方法，对锦西化工总厂环已酮车间利用环已醇脱氢生产环已酮的生产工艺过程进行了正交试验设计，应用方差分析方法得出了最佳生产工艺条件，同时给出了经济效益分析评价     

关于田口参数设计的专家评论

参数设计（也称稳健设计）是由日本质量专家田口提出的一种质量改进技术．它被认为是一种减少产品（或工艺）波动的经济有效方法．尽管直到１９８０年它才被引入到美国，然而田口有关质量改进思想的形成要追溯到５０年代．虽然当时日本国内田口思想没被普遍认识和接受，但一些公司和质量控制协会已在广泛使用该技术．１９８０年田口接受Ａｏｙａｍａ－ｇａｋｕｉｎ大学的资助并讲授他的质量改进思想．他接触了几个公司和研究院，包括ＡＴ＆Ｔ和Ｘｅｒｏｘ．在此之前美国人对田口思想的反映是持怀疑态度．但他设法吸引了一些人的兴趣．或许是８０年代初期由于对日本人质量实践的广泛关注，这种兴趣逐落增强．在ＡＴ＆Ｔ，Ｘｅｒｏｘ和其它地方及组织如美国供应者协会的一些人的帮助下，推动了田口思想在工业界的应用．由贝尔试验室的质量保证中心组织的１９８４和１９８５年两个Ｈｏｈｏｎｋ会议，在向统计界介绍田口思想以及促进一系列研究方面起了很大的作用．十年来已发现了许多关于四口参数设计思想的讨论和在工业上的许多应用． 现在我们已积累了相当多的经验，全面回顾一下参数设计及有关技术并提供给读者似乎合乎时宜．现已发表了对田口思想进行解释、概括和评论的一些书及文章．然而其中的大多数     

均匀设计及其应用（二）

均匀设计及其应用（二）方开泰第二章均匀设计的应用由于均匀设计要求的试验数较少，我们无法直接估计出各因素的主效应和交互效应，只能通过回归模型来建立试验指标（Ｙ）和各因素之间的关系，利用这种关系来寻求最优工艺条件或最优配方．试验设计的目的通常主要有二个，...     

威布尔分布或极值分布可靠度置信下限的回归表示

对于定数截尾样本，给出了基于极值分布的位置和尺度参数的最好线性无偏估计（BLUE），获得了威布尔分布的可靠度的点估计和置信限之间的回归模型，从而可由威布 尔可靠度的点估计根据回归方程得到可靠度的置信下限，省去了大量的用表，为实际工作者带来了极大的方便，计算结果表明，回归方程有很高的精度。     

Empirical likelihood inference for linear transformation models

Empirical likelihood inference is developed for censored survival data under the linear transformation models, which generalize Cox's [Regression models and life tables (with Discussion), J. Roy. Statist. Soc. Ser. B 34 (1972) 187-220] proportional hazards model. We show that the limiting distribution of the empirical likelihood ratio is a weighted sum of standard chi-squared distribution. Empirical likelihood ratio tests for the regression parameters with and without covariate adjustments are also derived. Simulation studies suggest that the empirical likelihood ratio tests are more accurate (under the null hypothesis) and powerful (under the alternative hypothesis) than the normal approximation based tests of Chen et al. [Semiparametric of transformation models with censored data, Biometrika 89 (2002) 659-668] when the model is different from the proportional hazards model and the proportion of censoring is high.     

Empirical likelihood inference for censored median regression with weighted empirical hazard functions

In recent years, median regression models have been shown to be useful for analyzing a variety of censored survival data in clinical trials. For inference on the regression parameter, there have been a variety of semiparametric procedures. However, the accuracy of such procedures in terms of coverage probability can be quite low when the censoring rate is heavy. In this paper, based on weighted empirical hazard functions, we apply an empirical likelihood (EL) ratio method to the median regression model with censoring data and derive the limiting distribution of EL ratio. Confidence region for the regression parameter can then be obtained accordingly. Furthermore, we compared the proposed method with the standard method through extensive simulation studies. The proposed method almost always outperformed the existing method.     

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In collecting clinical data, data would be censored due to competing risks or patient withdrawal. The statistical inference for censoring data is always based on the assumption that the failure time and censoring time is independent. But in practice the failure time and censoring time are often dependent. Dependent censoring make the job to deal with censoring data more complicated. In this paper, we assume that the joint distribution of the failure time variable and censoring time variable is a function of their marginal distributions. This function is called a copula. Under prespecified copulas, the maximum likelihood estimators for cox proportional hazards models are worked out. Statistical analysis results are carried by simulations. When dependent censoring happens, the proposed method will do better than the traditional method used in independent situations. Simulation results show that the proposed method can get efficient estimations.     

Life expectancy under random censorship

This paper deals with estimation of life expectancy used in survival analysis and competing risk study under the condition that the data are randomly censored by K independent censoring variables. The estimator constructed is based on a theorem due to Berman [2], and it involves an empirical distribution function which is related to the Kaplan-Meier estimate used in biometry. It is shown that the estimator, considered as a function of age, converges weakly to a Gaussian process. It is found that for the estimator to have finite limiting variance requires the assumption that the censoring variables be stochastically larger than the “survival” random variable under investigation.     

用对数线性模型比较香港居民在超市与便利店的购买行为

对于抽样调查比较香港居民在超市与便利店的购买行为所得的配对设计的方列联表数据，用对数线性模型进行分析。     

Information in Quantal Response Data and Random Censoring

In this paper we study interesting properties of Fisher and divergence type measures of information for quantal, complete and incomplete random censoring, and not censoring at all. It is shown that, while quantal random censoring is less expensive, it is less informative than complete random censoring. It is also shown that in experiments which are mixtures of quantal and complete random censoring, the information received from these experiments is a convex combination of quantal information and the information in complete random censoring. Finally, the "total information" property is studied, in which the information received by the uncensored experiment can be expressed as the sum of the information provided by random censoring and the loss of information due to censoring. The results for Fisher's measure of information are an extension of already known results to the multiparameter case. The investigation of the previous information properties for divergence type measures is a new element, as well as the comparison of byproducts of Fisher information matrices.     

逐步区间删失Weibull分布的Bayesian稳健设计

逐步区间删失是获取高可靠性产品相关信息的一种重要方法.文章研究了产品寿命服从Weibull分布,带有随机移除逐步区间删失寿命试验的最优设计问题.采用极大似然方法获取模型参数的估计及其信息矩阵.利用Bayesian方法处理模型参数未知情况下设计准则对模型参数的依赖问题,获得了模型参数估计的Bayesian稳健设计准则.在考虑试验费用有限制的条件下,给出了获得最优稳健设计非线性混合整数算法.同时对先验选取及约束参数设定的敏感性做了分析.数值结果表明文章提出的方法是有效可行的.     

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??In survival analysis, most existing approaches for analysing right-censored failure time data assume that the censoring time is independent of the failure time. However, investigators often face problems involving dependent censoring, i.e., failure time and censoring time are possibly dependent and they may be censored one another, especially in clinical trials. Without accounting for such dependence, survival distributions cannot be estimated consistently. Numerous attempts to model this dependence have been made. Among them, copula models are of particular interest because of their simple structure. Proportional hazard model analysis for informative right-censored data has been discussed in this paper. An Archimedean copula is assumed for the joint distribution function of failure time and censoring time variables. Under the conditions of identifiability of the parameter of the Archimedean copula, the maximum likelihood estimators of the parameter of Archimedean copula, the parameters and the cumulative hazard function of PH model are worked out. Extensive simulation studies show that the feasibility of the proposed method and the consistency of the estimators.