摘要:

Under the framework of a stochastic point process of failures, this paper discusses basic ways to characterize reliability. The distinction between the failure rate of a process, useful for repairable systems, and the failure rate of a distribution, useful for nonrepairable systems, is drawn. The paper then concentrates on modeling the wearout characteristics of repairable system reliability. Neither the homogeneous Poisson nor the renewal processes will suffice for this purpose. The nonhomogeneous Poisson process is appealing as a general wearout model, but it too has nonintuitive features; for example, the distribution of first failure determines the entire process. This leads us to search for other alternatives and to consider the reliability characteristics of general point processes of failures. Results pertaining to the appealing alternative of superimposed processes are reviewed.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486230

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

One form of the generalized gamma distribution brings out an association between the normal distribution and the extreme-value distribution. This relationship suggests chi-squared, Student'stand noncentraltapproximations for certain functions of the maximum likelihood estimators of the parameters of the extreme-value distribution. The accuracy of these approximations is studied by comparing them to existing Monte Carlo simulation results. These approximations provide simple procedures for obtaining approximate confidence intervals for the parameters, tolerance limits, and confidence limits on reliability for the Weibull or extremevalue distribution.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486231

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Statistics offered by Cook (1977) and Andrews and Pregibon (1978) purport to reveal influential observations in a regression analysis. Detailed examination of these statistics shows that two different types of influence are being measured and this is illustrated with examples derived from a set of data given by Mickey, Dunn, and Clark (1967). Recommendations are given for obtaining the best use of the statistics available.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486232

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A subdivision of theCp, statistic into individual components for each case is developed, and the properties of this statistic are outlined. This subdivision depends on both the change in fitted value or residual from the full model to the subset model and the change in leverage, but it does not depend directly on the values of the residuals. It is useful both as an aid in understandingCpand as a diagnostic procedure.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486233

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Schmee and Hahn (1979) suggested iterative least squares as a simple method for analyzing censored data. The application of this method to the analysis of the results of a fractional factorial experiment with censored observations is described and illustrated in this paper.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486234

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A new design criterion, called theBcriterion, is given for the situation where each experimental unit has some (categorical) covariate information. It directly addresses the question of balanced assignment over covariates, is simple in form, and does not involve matrix inversion. A simple and efficient algorithm for generating nearly baianced assignments is given. The basic element of the algorithm consists of switching and exchanging treatment assignments. The algorithm is illustrated on two examples.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486235

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

In this paper we develop a theory of optimal incomplete block designs for comparing several treatments with a control. This class of designs is appropriate for comparing simultaneouslyp≥ 2 test treatments with a control treatment (the so-called multiple comparisons with a control (MCC) problem) when the observations are taken in incomplete blocks of common sizek<p+ 1. For this problem we propose a new general class of incomplete block designs that arebalancedwith respect to (wrt)testtreatments. We shall use the abbreviation BTIB to refer to such designs. We study their structure and give some methods of construction. A procedure for making exact joint confidence statements for this multiple comparisons problem is described. By using a new concept of admissibility of designs, it is shown how “inferior” designs can be eliminated from consideration, and attention limited to a small class of BTIB designs that can be constructed from so-called generator designs in the minimal complete class of such designs. Some open problems concerning construction of BTIB designs are posed.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486236

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

At present, the first-order Bonferroni upper bound is the only practically useful tool for determining approximate critical values orpvalues for the maximum absolute studentized residual as a criterion for detecting a single outlier in a linear model. Available methods for assessing the accuracy of this bound require numerical integration and are difficult to apply routinely. We present a relatively simple alternative method that can be applied to any linear model and is suitable for routine use. The application to analyses of 2mfactorial experiments and regression models is illustrated with several examples.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486237

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Accurate bounds are presented for the fractiles of the maximum normed residual (which is often used to test for a single outlier) for two- and three-way layouts. It is shown that the second Bonferroni bound of the critical value, while not conservative, is an excellent approximation to the critical value, being much more accurate than the first Bonferroni upper bound. The third Bonferroni (upper) bound, which, although conservative, is expensive to calculate, agrees with the second bound to at least four decimal places for all factor combinations considered in this paper.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486238

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

In this paper the percentage points for the ESD, KUR, and RST many-outlier procedures that were introduced in Rosner (1975) are presented. A brief description of these procedures and some of the issues involved with evaluating their power are presented in Section 1. The algorithm used to estimate their percentage points is given in Section 2, and percentage points forN= 20(10)60(20)100 fork= 2(1)5 are presented. An example to illustrate the use of these percentage points is given in Section 3. Related investigations conducted by the author are reported in Section 4.

ISSN:0040-1706    

DOI:10.1080/00401706.1981.10486239

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor