A two sample wilcoxon test for progressively censored data

A two sairmle Wilcoxon type statistic is proposed for analyzing data for which the pN(0<p≤l) smallest observations are to be observed sequentially and the study terminated as soon as a statistically significant difference is obtained. The statistic is a special case of a general formulation due to chatteriee and Sen (1973), The asymptotic null distribution is presented and simulation studies reported which indicate chat the asymptotic distribution is useful for pN>60. Monte clarlo experiments comparing this statistic with another Wilcoxon type statistic proposed by Halperin and Ware (1974) are presented.     

略论技术发展的人本原则

人本原则的提出源于现代技术发展所带来的对人类的生存与发展构成严重威胁的自然生态危机、社会生态危机以及人的身心危机。人本原则就是要以全人类为本,以增进全人类的幸福,满足全人类的各种需要为本。人本原则要求技术的发展必须与优化人的生存环境联系起来;要促进技术朝人性化方向发展;技术的开发与应用要面向全人类;要提高责任意识。     

Survival models with two phases and length biased sampling

A survival model is presented in which all patients go through a first phase of disease; some then die and the remainder progress to a second phase of disease. The data observed are the path taken and the total sojourn time in the system but not the time, if ever, at which the second phase is entered. The sojourn time in each phase is assumed to be exponentially distributed with possibly different rates for the two phases. Themodel describes serious diseases that progress through one or two phases, and can be extended to multiple phases. The model is extended to account for several length-biased sampling situations. Censoring is considered in all models. Maximum like lihood estimates for the parameters involved exist, are consistent and are a symptotically normal. One of the proposed models is applied to data from the Veterans Administration involving a study of coronary arterial occlusive disease.     

生存·游戏·确证——论儿童文化的功能属性

儿童文化既构成儿童生存的现实又构成儿童对现实生存的理解、叙述和表达，儿童文化的这一深度图景，在功能属性上显现出儿童文化与儿童生存之间复杂的关联。只有当儿童游戏时，他才是儿童。潜藏在儿童文化中的游戏功能，对儿童的生存理解具有卓越性的意义。儿童文化是一个完整、多样、丰富的儿童世界，在生存理解所实现的秩序化方面，它显现为儿童对自我力量的确证和所属共同体的认同。     

Testing whether survival function is bivariate new better than used

We present statistical procedures to test that a life distribution is bivariate exponential against the alternative that it is bivariate new better than used (BNBU).     

The exponentiated-log-logistic geometric distribution: Dual activation

ABSTRACT

The log-logistic distribution is commonly used to model lifetime data. We propose a wider distribution, named the exponentiated log-logistic geometric distribution, based on a double activation approach. We obtain the quantile function, ordinary moments, and generating function. The method of maximum likelihood is used to estimate the model parameters. We propose a new extended regression model based on the logarithm of the exponentiated log-logistic geometric distribution. This regression model can be very useful in the analysis of real data and could provide better fits than other special regression models. The potentiality of the new models is illustrated by means of two applications to real lifetime data sets.     

Animal carcinogenicity experiments with and without serial sacrifice

Commonly used tests to detect carcinogenic potential of a test compound make extreme assumptions about the lethality of tumors, due to their occult nature. In this paper we compare a nonparametric test, which uses interim sacrifice to avoid such assumptions, with these tests using simulation based on the EDOl data. Results indicate that in the presence of a significant difference in the mortality rate with treatment, commonly used methods could fail to maintain the nominal significance level. However, when there is no difference in the mortality rate, such procedures are robust to the underlying assumptions about the lethality of tumors and more powerful than the nonparametric test using interim sacrifice.     

Maximum likelihood methods for complex sample data: logistic regression and discrete proportional hazards models

To estimate model parameters from complex sample data. we apply maximum likelihood techniques to the complex sample data from the finite population, which is treated as a sample from an i nfinite superpopulation. General asymptotic distribution theory is developed and then applied to both logistic regression and discrete proportional hazards models. Data from the Lipid Research Clinics Program areused to illustrate each model, demonstrating the effects on inference of neglecting the sampling design during parameter estimation. These empirical results also shed light on the issue of model-based vs. design-based inferences.     

A frailty modeling approach for parental effects in animal breeding

Survival models involving frailties are commonly applied in studies where correlated event time data arise due to natural or artificial clustering. In this paper we present an application of such models in the animal breeding field. Specifically, a mixed survival model with a multivariate correlated frailty term is proposed for the analysis of data from over 3611 Brazilian Nellore cattle. The primary aim is to evaluate parental genetic effects on the trait length in days that their progeny need to gain a commercially specified standard weight gain. This trait is not measured directly but can be estimated from growth data. Results point to the importance of genetic effects and suggest that these models constitute a valuable data analysis tool for beef cattle breeding.     

Simple nonparametric tests for a known standard survival based on censored data

It is often of interest in survival analysis to test whether the distribution of lifetimes from which the sample under study was derived is the same as a reference distribution. The latter can be specified on the basis of previous studies or on subject matter considerations. In this paper several tests are developed for the above hypothesis, suitable for right-censored observations. The tests are based on modifications of Moses' one-sample limits of some classical two-sample rank tests. The asymptotic distributions of the test statistics are derived, consistency is established for alternatives which are stochastically ordered with respect to the null, and Pitman asymptotic efficiencies are calculated relative to competing tests. Simulated power comparisons are reported. An example is given with data on the survival times of lung cancer patients.