ISO INTERNATIONAL STANDARD 28591 First edition 2017-10 Sequential sampling plans for inspection by attributes Plans d'echantillonnage progressif pour le controle par attributs Reference number ISO 28591:2017(E) ISO @ ISO 2017 st andar d999 IS0 28591:2017(E) COPYRIGHTPROTECTEDDOCUMENT @ IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +4122749 09 47 [email protected] www.iso.org ii @ IS0 2017 - All rights reserved st andard999 IS0 28591:2017(E) Contents Page Foreword ..iv Introduction ..vi 1 Scope. ..1 2 Normative references ..2 3 Terms and definitions ..2 4 Symbols and abbreviated terms .6 5 Principles of sequential sampling plans for inspection by attributes .7 6 Selection of a sampling plan .7 6.1 Producer's risk point and consumer's risk point .7 6.2 Preferred values of QpR and QcR ..8 6.3 Pre-operation preparations 8 Obtaining the parameters hA, hr and g ..8 6.3.1 6.3.2 Obtaining the curtailment values .8 7 Operation of a sequential sampling plan .8 7.1 Specification of the plan. .8 7.2 Drawing a sample item .8 7.3 Count and cumulative count .8 7.3.1 Count .8 7.3.2 Cumulative count .8 7.4 Choice between numerical and graphical methods .8 7.5 Numerical method. .9 7.5.1 Preparation of the acceptability table .9 7.5.2 Making decisions 9 7.6 Graphical method 10 7.6.1 Preparation of the acceptability chart .10 7.6.2 Making decisions. .11 8 Numerical example .12 9 Tables .12 Annex A (informative) Statistical properties of the sequential sampling plan for inspection by attributes .30 Bibliography .39 @ IS0 2017 - All rights reserved iii standard999