Accession Number:

ADA024436

Title:

On the Treatment of Grouped Observations in Life Studies.

Descriptive Note:

Interim technical rept.,

Corporate Author:

MISSOURI UNIV COLUMBIA DEPT OF STATISTICS

Personal Author(s):

Report Date:

1976-04-15

Pagination or Media Count:

16.0

Abstract:

Cox Regression models and life tables, J. Roy. Statist. Soc. 34B, 1972 presents a systematic study of the use of covariates in the analysis of life time. Coxs basic model is that of proportional failure rates. A particularly thorny point in theory and application is the treatment of tied observations. It appears that grouping rather than discrete time is the proper way to handle ties. This paper studies what to do with grouped observations. Maximum likelihood leads to ignoring intervals in which no failures occur. A logistic model, which makes explicit use of Coxs earlier binary data methods, is introduced and illustrated with a numerical example. When the grouping becomes fine this logistic model leads back to the proportional failure rate model suggested by Cox. Author

Subject Categories:

  • Statistics and Probability
  • Manufacturing and Industrial Engineering and Control of Production Systems

Distribution Statement:

APPROVED FOR PUBLIC RELEASE