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A Characterization of Marginal Distributions of (Possibly Dependent) Lifetime Variables which Right Censor each other
It is well known that the joint distribution of a pair of lifetime variables $X_1$ and $X_2$ which right censor each other cannot be specified in terms of the subsurvival functions $$P(X_2 > X_1 > x),\quad P(X_1 > X_2 > x)\text{and} P(X_1 = X_2 > x)$$ without additional assumptions su...
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Published in: | The Annals of statistics 1997-08, Vol.25 (4), p.1622-1645 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | It is well known that the joint distribution of a pair of lifetime variables $X_1$ and $X_2$ which right censor each other cannot be specified in terms of the subsurvival functions $$P(X_2 > X_1 > x),\quad P(X_1 > X_2 > x)\text{and} P(X_1 = X_2 > x)$$ without additional assumptions such as independence of $X_1$ and $X_2$. For many practical applications independence is an unacceptable assumption, for example, when $X_1$ is the lifetime of a component subjected to maintenance and $X_2$ is the inspection time. Peterson presented lower and upper bounds for the marginal distributions of $X_1$ and $X_2$, for given subsurvival functions. These bounds are sharp under nonatomicity conditions. Surprisingly, not every pair of distribution functions between these bounds provides a feasible pair of marginals. Crowder recognized that these bounds are not functionally sharp and restricted the class of functions containing all feasible marginals. In this paper we give a complete characterization of the possible marginal distributions of these variables with given subsurvival functions, without any assumptions on the underlying joint distribution of $(X_1, X_2)$. Furthermore, a statistical test for an hypothesized marginal distribution of $X_1$ based on the empirical subsurvival functions is developed. The characterization is generalized from two to any number of variables. |
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ISSN: | 0090-5364 2168-8966 |
DOI: | 10.1214/aos/1031594734 |