Frailty Models of Manufacturing Effects -- from Wolfram Library Archive

Title

Frailty Models of Manufacturing Effects

Authors

J. Wassell

G. Kulczycki

E. Moyer

Journal / Anthology

Lifetime Data Analysis

Year:

1995

Volume:

Page range:

161-170

Description

The median service lifetime of respirator safety devices produced by different manufacturers is determined using frailty models to account for unobserved differences in manufacturing processes and raw materials. The gamma and positive stable frailty distributions are used to obtain survival distribution estimates when the baseline hazard is assumed to be Weibull. Frailty distributions are compared using laboratory test data of the failure times for 104 respirator cartridges produced by 10 different manufacturers tested with three different challenge agents. Likelihood ratio tests indicate that both frailty models provide a significant improvement over a Weibull model assuming independence. Results are compared to fixed effects approaches to analysis of this data.

Subject

Mathematics > Probability and Statistics

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