ISO INTERNATIONAL STANDARD 3951-5 First edition 2006-03-01 Sampling procedures for inspection by variables - Part 5: Sequential sampling plans indexed by acceptance quality limit (AQL) for inspection by variables (known standard deviation) Regles d'echantillonnagepourles controlesparmesures Partie 5:Plans d'echantillonnagesequentiels indexés d'apres la limite d'acceptationde qualite(LAQ)pourI'inspectionparvariables (écart- type connu) Reference number ISO 3951-5:2006(E) @ISO2006 ISO3951-5:2006(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 @ISO2006 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either iSO at the address below or 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 2006-All rights reserved ISO 3951-5:2006(E) Contents Page Foreword Introduction 1 Scope 2 Normativereferences 3 Terms and definitions. 4 Symbols. 5 Acceptancequalitylimit(AQL) 6 Switching rules for normal, tightened and reduced inspection 7 Planning. 8 Choice between variables and attributes. 9 9 Choiceof inspection levelandAQL 10 Preliminary operations 11 Sampling plans .10 12 Further information.. 21 13 Examples 22 14 Tables.. Annex A(normative)Samplingplans for normal, tightened and reduced inspection.. AnnexB(normative)Criticalvaluesformaximumstandarddeviation. .29 AnnexC(informative)Statisticalcharacteristics 32 Bibliography.. 36 ISO 3951-5:2006(E) Foreword IsO (the International Organization for Standardization)is a worldwide federation of national standards bodies (Iso member bodies). The work of preparing International Standards is normally carried out through IsO non-governmental, in liaison with IsO, also take part in the work. iso collaborates closely with the International ElectrotechnicalCommission (IEC)onallmattersofelectrotechnicalstandardization 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 memberbodies casting a vote Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. sO shall not be held responsible for identifying any or all such patent rights. ISO3951-5 was prepared by Technical Committee ISO/TC69,Applications of statistical methods, SubcommitteeSc 5,Acceptancesampling. This edition cancels and replaces Annex A of isO 8423:1991, which has been technically revised to greatly improve its compatibility with the sampling systems in IsO3951-1. variables: inspectionforasinglequalitycharacteristicanda singleAQL Part5:Sequential samplingplans indexedbyacceptancequality limit(AQL)for inspectionbyvariables (known standard deviation) The following parts are under preparation: Part2:General specification forsingle samplingplans indexedbyacceptancequality limit(AQL)for lot-by-lot inspectionof independentqualitycharacteristics Part3:Doublesamplingschemes indexedbyacceptancequality limit(AQL)forlot-by-lot inspection ISO 3951-5:20