Accession Number : AD0663096

Title :   ON SMALL SAMPLE PROBABILITY LIMITS FOR CONTROL CHARTS.

Descriptive Note : Technical rept.,

Corporate Author : STANFORD UNIV CALIF DEPT OF STATISTICS

Personal Author(s) : Yang,Chung-How ; Hillier,Frederick S.

Report Date : 08 DEC 1967

Pagination or Media Count : 43

Abstract : The paper considers the problem of how a small number of subgroups may be used to set control limits for Shewhart control charts so that these limits will yield the desired probability of a Type I error on each subgroup tested. Such small sample probability limits are developed both for testing future subgroups and, by suitable modifications, for retrospectively testing the initial subgroups. To increase the power of the test, the sample variance or average subgroup variance is used to establish these limits for several new charts for controlling the central tendency or dispersion of the process. In addition, previous derivations of the small sample probability limits for testing future subgroups on the X bar and R chart are supplemented here by deriving the corresponding limits for retrospective testing. Finally, an alternative method is presented for calculating probability limits for the p chart and c chart when the process parameter is either known or prespecified as a target value. Tables of the factors for calculating the various probability limits also are presented wherever appropriate. (Author)

Descriptors :   (*QUALITY CONTROL, SAMPLING), (*PRODUCTION CONTROL, SAMPLING), (*SAMPLING, MANAGEMENT PLANNING AND CONTROL), STATISTICAL ANALYSIS, PROBABILITY, STATISTICAL DISTRIBUTIONS, ANALYSIS OF VARIANCE, TABLES(DATA)

Subject Categories : Operations Research
      Mfg & Industrial Eng & Control of Product Sys

Distribution Statement : APPROVED FOR PUBLIC RELEASE