7087 International Standard (ISO INTERNATIONALORGANIZATIONFOR STANDARDIZATION+MEXKAYHAPOAHAROPTAHM3ALMWRIOCTAHAAP PTW3ALWMORGANISATIONINTERNATIONALEDENORMALISATION Ferroalloys - Experimental methods for the evaluation of the quality variation and methods for checking the precision of sampling Ferro-alliages - Methodes experimentales d'evaluation de la variation de qualite et methodes de controle de la fidelite de Iéchantillonnage First edition--1984-11-01 SO7087-1984(E) UDC 669.15-198 :620.11 Ref. No. 1SO 7087-1984 (E) Descriptors :ferroalloys, estimation, quality, variation, experimental data, sampling Price based on 13 pages Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (Iso member bodies).The work of preparing International Standards isnormally carried out through ISo technical committees.Each member body interested ina subject forwhich a technical committeehas beenestablished has the right to be represented on that committee. International organizations,govern- mental and non-governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the Iso Council. They are approved in accordance with ISo procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 7087 was prepared by Technical Committee ISO/TC 132, Ferroalloys. @International Organization for Standardization, 1984 Printed in Switzerland Contents Page 1 Scope and field of application 2References 3Generalrequirementsforexperiment 3.1 Qualityvariation Qualitycharacteristic. 2 3.3 Evaluation of thequality variation of ferroalloys 2 3.4 Consignments for experiment 2 3.5 Method for sampling and chemical analysis 2 3.6 Number of experiments. 2 Order of chemical determinations 2 4Experimental methods 2 4.1 Typesofexperiment 2 4.2 Typel. 2 4.3 Type lI 3 5Methods for analysis of experimental data 9 5.1 Selection of the method 9 5.2Method for data analysis for random sampling 9 5.3 Method for data analysis for two-stage sampling 9 6 Expressionofexperimentalresults 10 6.1 Random sampling 10 6.2 Two-stage sampling 10 7 Estimation for precision of sampling . 10 7.1 Method for random sampling. 10 7.2 Method for two-stage sampling 10 7.3Actions after review of estirnated results Annex Example of two other methods for the calculation of quality variation value (for two-stage sampling) for an experiment of 10 consignments .. ili Coovriaht International Oraanization for Standardization