| Some New Approaches to Multivariate Probability Distributions |
SEP 86 |
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| Authors:
D. N. Shanbhag; Samuel Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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 | This paper extends and generalizes to the multivariate set-up earlier investigations related to expected remaining life functions and general hazard measures including representations and stability theorems for arbitrary probability distributions in terms of these concepts. |
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| Note on a Characterization of Exponential Distributions |
JUL 86 |
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| Authors:
Samuel Kota; F. W. Steutel; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| This document shows that a certain relation is satisfied if and only if the components of Y are multiples of a single exponentially distributed random variable. |
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| Estimation from Binomial Data with Classifiers of Known and Unknown Imperfections |
JUL 86 |
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| Authors:
Norman L. Johnson; Samuel Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Observations from inspection by a 'test' method and a standard method are combined to provide estimators of population proportion, and of probabilities of misclassification for the test method. Results of Hochberg and Tenenbein and of Albers and Veldman are extended to the case where the standard method is not perfect, but its misclassification probabilities have known values. Both moment and maximum likelihood estimators are considered and some asymptotic properties of ... |
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| Statistical Effects of Imperfect Inspection Sampling. 3. Screening (Group Testing) |
MAR 86 |
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| Authors:
Norman L. Johnson; Samuel Kotz; Robert N. Rodriguez; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| This paper, the third in a series, describes the effects of imperfect inspection on screening (group testing) acceptance sampling procedures. These procedures are based on first grouping items and testing the group as a whole for presence or absence of nonconforming (NC) items proceeding to individual testing only if such presence is indicated. If sampling is perfect, the procedure can reduce the expected amount of testing, especially if the proportion ... |
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| Statistical Effects of Imperfect Inspection Sampling: II. Double Sampling and Link Sampling. Revision |
OCT 85 |
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| Authors:
N. L. Johnson; S. Kotz; R. N. Rodriguez; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| This paper, the second in a series of three, utilizes the basic distributions established in the first paper to assess the effect of inspection errors in three types of acceptance procedures: double sampling, link and partial link sampling. Additional keywords: Acceptance sampling plans; Binomial distribution; Compound distribution; Hypergeometric distribution; Inspection error tables. |
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| Estimation of Population Proportion and of Probabilities of Misclassification from Imperfect Binomial Data by Comparison with Results of a Standard Method of Known Imperfection |
AUG 85 |
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| Authors:
N. L. Johnson; S. Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Observations from inspection by a test method and a standard method are combined to provide estimators of population proportion, and of probabilities of misclassification for the test method. Results of Hochberg and Tenenbein (1983) and of Albers and Veldman (1984) are extended to the case where the standard method is not perfect, but its misclassification probabilities have known values. Both moment and maximum likelihood estimators are considered and some asymptotic ... |
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| A Survey of some Recent Results in Continuous Univariate Distributions |
JUL 85 |
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| Authors:
S. Kotz; N. L. Johnson; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Pursuant to the authors on advances in discrete distributions (Johnson and Kotz (1982)) they have commenced work on advances in continuous univariate distributions from 1971 onwards. In contrast to the situation for discrete distributions, this field was markedly more fully developed by 1970, in regard to both variety of available distributions and sophistication of methods for fitting. Possibly as a consequence, there is now available a number of very useful ... |
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| Estimation by Moments in a Model of Faulty Inspection |
JUN 85 |
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| Authors:
M. Shisong; S. Kotz; N. L. Johnson; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Methodology developed by Blischke is applied to estimate the parameters in a model of faulty inspection, and to obtain approximate formulae for the variances of these estimators. Key words: Attribute inspection; Binomial distribution; Factorial Moments; Hypergeometric distribution; Mixtures; Moment Method. |
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| A Modified Repair Strategy for Two-Component Systems with Revealed and Unrevealed Faults |
MAY 85 |
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| Authors:
N. L. Johnson; S. Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Some consequences of a modified repair system for Phillips' model for a two component system are discussed. In the original model, both components are repaired whenever a revealed fault occurs; in the modified model only faulty components are repaired. Specifically (1) the distribution of time from the initial state up to discovery of an unrevealed fault, (2) the expected propagation of the time during which these exists an unrepaired fault, ... |
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| Effects of Inspection Errors on Curtailed Dorfman-Type Procedures |
MAR 85 |
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| Authors:
S. Kotz; M. Shisong; N. L. Johnson; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| The effects of inspection error on a two-stage procedure for identification of defective units is studied. The first stage is intended to provide the number of defective units in a group of n units; the second stage consists of individual inspection until the status of all units is (apparently) established. Keywords include: Attribute inspection, Binomial distribution, Hypergeometric distribution, Mixtures, and Sequential methods. |
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| Statistical Effects of Imperfect Inspection Sampling. II. Double Sampling, Link Sampling and Grading |
MAR 85 |
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| Authors:
N. L. Johnson; S. Kotz; R. N. Rodriguez; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| This paper, the second in a series of three, utilizes the basic distributions established in the first paper to assure the effect of inspection errors in double sampling, link and partial link sampling and in grading acceptance procedures. Originator-supplied keywords include: Acceptance sampling plans, Binomial distribution, Compound distribution, Double sampling, Link sampling, Hypergeometric distr., and Inspection error tables. |
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| An Estimation Problem in Faulty Inspection Sampling. Revised |
JUN 1984 |
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| Authors:
N. L. Johnson; S. Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Suppose samples of size n are chosen at random from lots of size N and examined for the presence (or absence) of a certain type (or types) of defect. If inspection is not perfect, there may be a probability, p, of failing to detect a defect when it is, in fact, present. It is desired to estimate p from records of the number of items found to have the defect(s) ... |
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| Correlation Structure in Iterated Farlie-Gumbel-Morgenstern Distributions |
JAN 1984 |
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| Authors:
J. S. Huang; Samuel Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| In this note the authors determine the natural parameter space of the iterated FGM distribution, and thereby show that the maximum correlation is higher than what was previously known. They also show that one single iteration can result in tripling the covariance for certain marginals and that there exist no marginals for which the single iteration will bring about higher negative correlation. (Author) |
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| Inspection Errors in Link Sampling |
DEC 1983 |
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| Authors:
S. Kotz; N. L. Johnson; R. N. Rodriquez; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Results of an investigation into the sensitivity to two types of inspection error of link sampling procedures described by Harishchandra and Srivenkataramana are reported. Relevant compound distributions are derived. Some comparisons with results obtained in a similar investigation for standard double sampling are also given. (Author) |
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| Moment Estimators of Defect Pattern Frequencies, Allowing for Inspection Error |
SEP 1983 |
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| Authors:
Norman L. Johnson; Samuel Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Unbiased estimators of the number of individuals in a lot possessing various patterns of types of defects are constructed. Explicit formulas are given for cases of two and three types of defect. Application of the formulas requires knowledge of the probabilities of various kinds of errors in the inspection process. |
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| Eigenvalues and Eigenvectors of Correlation Matrices with Special Structures: Applications to Factor Analysis of Common Stock Rates of Return |
AUG 1983 |
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| Authors:
Samuel Kotz; W. L. Pearn; Dean W. Wichern; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| The authors derive the general forms for the eigenvalues and eigenvectors of certain correlation matrices with special structures. Our inquiry was motivated by an analysis of the rates of return on common stocks. Stocks within certain groups (for example, stocks within the same industry) may be equally correlated and the correlations between stocks in different groups, although equal, may be smaller in magnitude than the within group correlations. |
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| Some Distributions Arising as a Consequence of Errors in Inspection |
JUL 1983 |
15 pages |
| Authors:
Norman L. Johnson; Samuel Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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 | In this paper the authors survey and consolidate their investigations during this years 1980-1983 dealing with consequences of errors in inspection sampling models. Some indication of the current and future research is given. Selective bibliography is presented. (Author) |
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| Some Multivariate Distributions Arising in Faulty Sampling Inspection |
JUN 1983 |
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| Authors:
Norman L. Johnson; Samuel Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| In the present paper we extend in two ways some results relating to the study of distributional aspects of effects of errors in inspection sampling: (1) Multistage sampling with k successive samples samples involving the possibility of two types of errors in inspection (classifying a defective individual as non-defective, or a non-defective as defective); (2) Single-stage sampling considering several types of defects of which only one is tested on inspection. ... |
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| Some Distributions Arising from Faulty Inspection with Multitype Defectives, and an Application to Grading |
APR 1983 |
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| Authors:
Samuel Kotz; Norman L. Johnson; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Continuing their investigation of distributions arising from faulty and incomplete inspection from a finite population (Johnson et al (1980), Comm. in Stat. A9 917-922, Kotz and Johnson, ibid, All, 1997-2016) the authors investigate cases when inspection is not restricted to a single type of defect. Applications to grading problems, when grading is based on sets of defects found by sampling inspections, are discussed. |
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| Some Replacement - Times Distributions in Two-Component Systems |
DEC 1982 |
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| Authors:
Norman L. Johnson; Samuel Kotz; MARYLAND UNIV COLLEGE PARK DEPT OF MANAGEMENT SCIENCES AND STATISTICS
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| Considered herein is a system consisting of two modules, one of which cannot be easily inspected, while the other is monitored continuously. A fault developing in the first model is called unrevealed (U) while the one in the second module (which is assumed to be detected immediately) is called revealed (R). It is supposed that repairs are initiated as soon as an R is observed, but not otherwise. This paper ... |
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