ISO/TR TECHNICAL REPORT 8550-3 First edition 2007-06-01 Guidance on the selection and usage of acceptance sampling systems for inspection of discrete items in lots Part 3: Sampling by variables Lignes directrices pour la sélection d'un systeme, d'un programme ou d'un plan d'échantillonnage pour acceptation pour le controle d'unites discretes en lots- Partie 3: Echantillonnage par variables Reference number ISO/TR 8550-3:2007(E) @ ISO 2007 y IHS under ted without license from IHS Not for Resale ISO/TR 8550-3:2007(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The IsO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by IsO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below COPYRIGHTPROTECTEDDOCUMENT @ISO2007 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, IsO's member body in the country of the requester. ISO copyright office Case postale 56. CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland @ ISO 2007 - All rights reserved ed without license from IHS Not for Resale ISO/TR 8550-3:2007(E) Contents Page Foreword. Introduction 1 Scope 2 Normative references 3 Normality 4 Types of control.... 12 5 Forms of acceptance criteria.. 6 InternationalStandardsforacceptancesamplingoflotsbyvariables 7 Effect on the selection process of market and production conditions. Annex A (normative) Normal probability paper Bibliography 39 Copyright internatinal organizaio far standardizalion ghts reserved ii IHS unde se from IHS Not for Resale ISO/TR8550-3:2007(E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies technicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeer non-governmental, in liaison with isO, also take part in the work. iso collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/lEc Directives, Part 2. adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In exceptional circumstances, when a technical committee has collected data of a different kind from that simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature and does not have to be reviewed until the data it provides are considered to be no longer valid or useful. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. IsO shall not be held responsible for identifying any or all such patent rights. ISO/TR 8550-3 was prepared by Technical Committee ISO/TC 69, Applications of statistical methods, Subcommittee SC 5, Acceptance sampling. ISO/TR 8550:1994. IsO/TR 8550 consists of the following parts, under the general title Guidance on the selection and usage of acceptance sampling systems for inspection of discrete items in lots: Part1:Acceptance sampling Part 3: Samp