摘要:

This paper addresses the question: “What is an appropriate statistical procedure for testing the electronic reliability of nuclear powered cardiac pacemakers?” A sequential test procedure is described, assuming a constant failure rate, together with a method for testing the validity of this assumption. The methods described herein were recommended by the authors to the U.S. Atomic Energy Commission, Directorate of Licensing, and subsequently appeared asThe Generic Environmental Statement on Routine Use of Plutonium Powered Cardiac Pacemakers, July, 1976, Document NUREG 0060, issued by the Nuclear Regulatory Commission.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489664

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

As an expedient for constructing approximate confidence intervals for complicated parametric functions, it is suggested that fiducial or Bayes intervals be generated by Monte Carlo methods. In each application these may be empirically tested for their frequency properties. The method was applied to the overall seeding effect in a rainfall modification experiment, and it is concluded that a useful approximate confidence interval was obtained.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489665

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The probability density function for the number of insects in a grain bulk, as indicated by a sample, is derived using the Bayesian method with a uniform prior. The p.d.f. is negative binomial and is shown to be approximately chi-square for small samples. Sampling procedures are discussed.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489666

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

For two initial process levels,po′ = 0.01 andpo′ = 0.05, minimum cost p-charts are presented for 36 sets of cost data and three degrees of shift in the process mean. Minimum cost designs are also given for other special cases. Actually minimum cost designs are derived for np-charts and converted to p-charts. The degrees of shift are expressed as 0.1, 0.5 and 1.0 multiples of the initial process standard deviation. This has some but not a full stabilizing effect. In general it is found that small shifts require larger samples taken less frequently, but generally with a lower overall intensity of sampling. It is also found that with rare exceptions charts designed to detect small shifts have acceptance limits of zero. The effects of variations in the cost parameters and in the rate of occurrence of the assignable cause are also presented in the paper and a brief comparison is made with a paper on p-charts by W. K. Chiu and another by D. C. Montgomery, J. F. Mance and R. G. Herkes.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489667

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

In a previous paper [3], the authors presented large sample optimum accelerated test plans to estimate the survival probability at a design stress assuming a linear logistic model, i.e. a linear relationship between stress and the log survival odds at that stress. The optimum plans required testing at two accelerated stresses with a larger allocation of units assigned to the lower of the two stresses. In practice, however, it is often desirable to conduct the accelerated tests at more than two stresses and/or use equal or otherwise prespecified allocation. In this paper we compare the large sample variance of each of ten such non-optimum test plans (and also that of testing exclusively at the design stress) with that of the optimum plan under a variety of conditions.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489668

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A model resembling the Barlow-Scheuer reliability growth model [I] is examined from a Bayesian perspective. A Dirichlet prior distribution is assumed on the three parameters of the model, i.e. the probability of an inherent failure, the probability of an assignable-cause failure, and the probability of success. The model assumes that a subsystem is tested in independent stages. At each stage, the posterior distribution is a Dirichlet distribution, or a mixture of Dirichlet distributions, depending on whether the investigator can identify with certainty which of the assignable-failure causes are removed when those discovered during testing are corrected. Methodology is developed for estimating reliability at the end of each stage of testing and for obtaining lower and upper bounds for system reliability. The Barlow-Scheuer data are reexamined using the approach developed herein.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489669

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A robust adaptive estimation procedure for location estimation problems is developed. Classification in this procedure is done on the basis of skewness and tailweight, using two statistics that are ratios of linear functions of sample order statistics. The associated estimators are of the general type known as M-estimators, Following the development of the adaptive location estimation procedure, an application to thekpopulation selection problem is given. Monte Carlo results show the superiority of the adaptive procedure to the sample means procedure, the rank sum procedure, and the previously developed adaptive procedure of Randles, Ramberg, and Hogg.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489670

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Minimum variance quadratic unbiased estimators (MIVQUE's) of variance components from unbalanced data are obtained for the one-way classification random model under normality. Explicit, computable expressions are given for the estimators, their variances, and their covariance. The variance expressions provide readily-calculated lower bounds for the variances of any quadratic unbiased estimators of the variance components.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489671

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A strategy for selecting subsets of variables from a given linear model in a mixture system is discussed. The purpose is to achieve better fitting surfaces for estimation of the response in an experimental region of interest. A criterion is proposed which can be used for screening variables as well as model reduction and is illustrated with examples.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489672

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A class of linear estimators, called Bayes linear estimators, is developed by finding, among all linear estimators, ones which have least average total mean squared error, averaged over parameter points. Ridge, generalized ridge, restricted least squares, subset least squares, least squares, best, and generalized inverse linear estimators are all either Bayes linear estimators or limits of Bayes linear estimators. Results on Bayes linear estimators are extended to affine estimators. “Bootstrapping” procedures, in which the data are recycled in the guise of prior information, are discussed.

ISSN:0040-1706    

DOI:10.1080/00401706.1978.10489673

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor