双参数指数分布无失效数据的参数估计

文章对双参数指数分布的无失效数据（ｔｉ，ｎｉ），给出了参数μ和σ的修正极大似然估计和最小二乘估计，并给出了失效概率ｐｉ＝ｐ｛Ｔ＜ｔｉ｝的Ｂａｙｅｓ估计和多层Ｂａｙｅｓ估计，从而可以得到无失效数据可靠度的估计。最后，结合实际问题进行了计算。     

无失效数据的多层Bayes可靠性分析

本文对无失效数据（ti,ni）在时刻ti的失效概率pi＝p｛T＜ti｝的先验分布为不完全Beta分布时，给出了pi的多层Bayes估计，由此可以得到无失效数据可靠度的估计．     

指数分布参数多层Bayes和E Bayes估计的性质

本文讨论无失效数据下指数分布参数多层Bayes估计和E Bayes估计的性质,在超参数分别取两种不同的先验分布下,证明参数的多层Bayes估计和E Bayes估计渐近相等,且多层Bayes估计值小于E Bayes估计值.     

指数分布无失效数据的统计分析

本文讨论了指数分布的无失效数据(ti,ni),利用指数分布的凸性和其特性一无记忆性,给出了可靠度的多层Bayes估计,进而得到参数θ的加权最小二乘估计.     

无失效数据的统计分析

本文利用分布函数的凹凸性质给出了各检测时刻失效概率Ｐｉ的相互关系，作为先验信息，我们得到Ｐｉ（ｉ＝１，ｍ）的Ｂａｙｅｓ估计，进而估计出母体参数，最后对实际数据进行了计算。     

双参数指数分布无失效数据的Bayes估计

本文对双参数指数分布的无失效数据（t_i,n_i）,在时刻t_i的失效概率P_i=P{T＜t_i}的先验分布为截尾指数分布时,给出了P_i的Bayes估计,从而可以得到无失效数据可靠度的估计．最后,结合实际问题进行了计算．     

无失效数据的Bayes和多层Bayes估计

对无失效数据的研究 ,是近些年来遇到的一个新问题 ,在实际问题中迫切需要解决 ,这项工作具有理论和实际应用价值 .本文对无失效数据 (ti,ni) ,在时刻ti 的失效概率pi=p{T 相似文献   

无失效数据情形参数的综合估计

本对指数分布的无失效数据,在引进失效信息后,在先验分布为Gamma分布时,给出了失效率的多层Bayes估计和综合Bayes估计,并给出了无失效数据情形可靠度的综合估计,还结合实际问题进行了计算。     

无失效数据情形失效率的综合估计

对指数分布的无失效数据，提出了无失效数据情形失效率的综合估计法。在失效率的先验分布为截尾Gamma分布时，给出了失效率的多层Bayes估计。在引进失效信息后，在失效率的先验分布为截尾Gamma分布时，给出了失效率的多层Bayes估计和综合估计，并给出了可靠度的综合估计，结合实际问题进行了计算。     

正态分布场合下只有一个失效数据的参数估计

本文利用母体分布函数的凹凸性以及各检测时刻失效概率的取值小的可能性大,取值大的可能性小的性质,给出了各检测时刻失效概率的估计,从而得到母体参数的最小二乘估计,最后将此方法应用于实际例子,所得结果较为稳健。     

Statistical Inference for the Location and Scale Parameters of the Skew Normal Distribution

In this paper, we consider the problem of estimating the location and scale parameters of the skew normal distribution introduced by Azzalini. For this distribution, the classic maximum likelihood estimators(MLEs) do not take explicit forms. We approximate the likelihood equations and derive explicit estimators of the parameters. The bias and variance of the estimators are investigated and Monte Carlo simulation studies show that the estimators are as efficient as the classic MLEs. We demonstrate that the probability coverages of the pivotal quantities (for location and scale parameters) based on asymptotic normality are unsatisfactory, especially when the sample size is small. The use of unconditional simulated percentage points of these quantities is suggested. Finally, a numerical example is used to illustrate the proposed inference methods.     

截尾样本下,具有共同尺度参数的多总体指数分布的参数估计

讨论了在截尾样本下,具有共同尺度参数的多总体指数分布的参数估计问题,证明了尺度参数及位置参数的最佳仿射同变估计是不容许的,且给出了相应的改进估计.     

A Family of Estimators of Finite-Population Distribution Function Using Auxiliary Information

This paper considers the problem of estimating the finite-population distribution function and quantiles with the use of auxiliary information at the estimation stage of a survey. We propose the families of estimators of the distribution function of the study variate y using the knowledge of the distribution function of the auxiliary variate x. In addition to ratio, product and difference type estimators, many other estimators are identified as members of the proposed families. For these families the approximate variances are derived, and in addition, the optimum estimator is identified along with its approximate variance. Estimators based on the estimated optimum values of the unknown parameters used to minimize the variance are also given with their properties. Further, the family of estimators of a finite-population distribution function using two-phase sampling is given, and its properties are investigated.      

Classes of improved estimators for parameters of a Pareto distribution

The problem of estimating parameters of a Pareto distribution is investigated under a general scale invariant loss function when the scale parameter is restricted to the interval (0, 1]. We consider the estimation of shape parameter when the scale parameter is unknown. Techniques for improving equivariant estimators developed by Stein, Brewster–Zidek and Kubokawa are applied to derive improved estimators. In particular improved classes of estimators are obtained for the entropy loss and a symmetric loss. Risk functions of various estimators are compared numerically using simulations. It is also shown that the technique of Kubokawa produces improved estimators for estimating the scale parameter when the shape parameter is known.     

The Minimax Estimator of Stochastic Regression Coefficients and Parameters in the Class of All Estimators

In this paper, the authors address the problem of the minimax estimator of linear combinations of stochastic regression coefficients and parameters in the general normal linear model with random effects. Under a quadratic loss function, the minimax property of linear estimators is investigated. In the class of all estimators, the minimax estimator of estimable functions, which is unique with probability 1, is obtained under a multivariate normal distribution.     

Inference for a simple step-stress model based on ordered ranked set sampling

In this paper, we considered the inference problem on simple step-stress accelerated life test data from one-parameter exponential distribution under type-I censored ordered ranked set sample with cumulative exposure model. The Bayesian estimators and credible intervals for the model parameters are developed and compared with the corresponding estimators based on simple random sampling. Two real data sets and numerical simulation evaluations are presented to illustrate all the results developed here. The simulation study indicated that the proposed Bayes estimators and credible intervals based on ordered ranked set sampling performed better than their counterparts using simple random sampling.     

Estimation of the parameters of an exponential distribution under constrained location

In this paper, the problem of estimating parameters of an exponential population is studied under quadratic loss functions. The location parameter of the distribution is assumed to be bounded above by a known constant. Various classes of estimators are derived using integral expression of risk difference (IERD) method of Kubokawa (1994). Some complete class results are also established.     

Bivariate Birnbaum–Saunders distribution and associated inference

Univariate Birnbaum–Saunders distribution has been used quite effectively to model positively skewed data, especially lifetime data and crack growth data. In this paper, we introduce bivariate Birnbaum–Saunders distribution which is an absolutely continuous distribution whose marginals are univariate Birnbaum–Saunders distributions. Different properties of this bivariate Birnbaum–Saunders distribution are then discussed. This new family has five unknown parameters and it is shown that the maximum likelihood estimators can be obtained by solving two non-linear equations. We also propose simple modified moment estimators for the unknown parameters which are explicit and can therefore be used effectively as an initial guess for the computation of the maximum likelihood estimators. We then present the asymptotic distributions of the maximum likelihood estimators and use them to construct confidence intervals for the parameters. We also discuss likelihood ratio tests for some hypotheses of interest. Monte Carlo simulations are then carried out to examine the performance of the proposed estimators. Finally, a numerical data analysis is performed in order to illustrate all the methods of inference discussed here.     

Log-logistic parameters estimation using moving extremes ranked set sampling design

In statistical parameter estimation problems, how well the parameters are estimated largely depends on the sampling design used. In the current paper, a modification of ranked set sampling(RSS) called moving extremes RSS(MERSS) is considered for the estimation of the scale and shape parameters for the log-logistic distribution. Several traditional estimators and ad hoc estimators will be studied under MERSS. The estimators under MERSS are compared to the corresponding ones under SRS. The simulation results show that the estimators under MERSS are significantly more efficient than the ones under SRS.     

Maximum Likelihood Estimation of Asymmetric Laplace Parameters

Maximum likelihood estimators (MLE's) are presented for the parameters of a univariate asymmetric Laplace distribution for all possible situations related to known or unknown parameters. These estimators admit explicit form in all but two cases. In these exceptions effective algorithms for computing the estimators are provided. Asymptotic distributions of the estimators are given. The asymptotic normality and consistency of the MLE's for the scale and location parameters are derived directly via representations of the relevant random variables rather than from general sufficient conditions for asymptotic normality of the MLE's.