Professional paper
The estimate of OC-functions for attribute sampling plans
M. Filajdić
; Prehrambeno-biotehnološki fakultet, Pierottijeva 6, 10000 Zagreb
Milana Ritz
Nada Vahčić
Mirjana Hruškar
Abstract
IDF - organisation has two standards for sampling milk and milk products: IDF - Standard 50B (1980) as a guide to sampling techniques and IDF - Standard 113 (1982) as standard for sampling by attributes. (IDF - STANDARD 50B, 1980: IDF - STANDARD 113, 1982). The last one is identical to ISO-5538 :1987 Standard »Milk and milk products - sampling - Inspection by attributes. (ISO-5538, 1987).The sampling- theory used in these standards is based on classifying a unit as "good" or "defective". A "good" unit is one which meets the requirements of a standard, a "defective" unit is one which does not. (Montgomery, 1985). Since these standards do not offer explanation of how to make a construction for OC - functions of the given sampling plans, and these functions are very important in practice, the procedure for construction of the OC - curve for a given AQL, RQL, α- and ß- probability will be demonstrated in this article if anyone does not want or does not have the possibility to use the schemes from the standards. The calculation of sample size (n), as an acceptance number (c) and OC-function's plan by arcsin transformation was made by Graf (1987) and Guenther (1977) iterative algorithme, while the OC-function of the plans was reached by Binomial distribution. The comparison of the calculated crucial plan's parameters with those given by the contract of two partners, (table 2) shows in favour, to attributive sampling plan. L (P/20:l).
Keywords
standards for milk and milk-products sampling; the sampling theory; sampling plans; attributive sampling plan; procedure for construction of the OC-curve; sample's size calculation; acceptance number calculation
Hrčak ID:
95408
URI
Publication date:
19.9.1993.
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