1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-23358-7 SANS 11843-2:2009Edition 1 and ISO tech. corr. 1ISO 11843-2:2000Edition 1 and tech. corr. 1SOUTH AFRICAN NATIONAL STANDARD Capabil
4、ity of detection Part 2: Methodology in the linear calibration case This national standard is the identical implementation of ISO 11843-2:2000 and ISO technical corrigendum 1, and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Divisi
5、on 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 11843-2:2009 Edition 1 and ISO tech. corr. 1 ISO 11843-2:2000 Edition 1 and tech. corr. 1 Table of changes Change No. Date Scope ISO tech. corr. 1 2007 Corrected to add pa
6、rts to the list of parts in the foreword, to replace normative references and to modify equations. National foreword This South African standard was approved by National Committee SABS TC 169, Applications of statistical methods, in accordance with procedures of the SABS Standards Division, in compl
7、iance with annex 3 of the WTO/TBT agreement. This SANS document was published in September 2009. Reference numberISO 11843-2:2000(E)ISO 2000INTERNATIONALSTANDARDISO11843-2First edition2000-05-01Capability of detection Part 2:Methodology in the linear calibration caseCapacit de dtection Partie 2: Mth
8、odologie de ltalonnage linaireSANS 11843-2This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 11843-2:2000(E)PDF disclaimerThis PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or v
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11、use by ISO member bodies. In the unlikely eventthat a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2000All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, ele
12、ctronicor mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member bodyin the country of the requester.ISO copyright officeCase postale 56 Gb7 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 734 10 79E-mail copyrightiso.ch
13、Web www.iso.chPrinted in Switzerlandii ISO 2000 All rights reservedSANS 11843-2This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 11843-2:2000(E) ISO 2000 All rights reserved iiiContentsForeword.ivIntroduction.v1 Scope 12 Normative reference
14、s 13 Terms and definitions .24 Experimental design24.1 General24.2 Choice of reference states24.3 Choice of the number of reference states, I, and the (numbers of) replications of procedure, J,K and L 35 The critical values ycand xcand the minimum detectable value xdof a measurement series .35.1 Bas
15、ic assumptions 35.2 Case 1 Constant standard deviation.45.3 Case 2 Standard deviation linearly dependent on the net state variable66 Minimum detectable value of the measurement method 97 Reporting and use of results107.1 Critical values.107.2 Minimum detectable values10Annex A (normative) Symbols an
16、d abbreviations.11Annex B (informative) Derivation of formulae14Annex C (informative) Examples .20Bibliography24SANS 11843-2This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 11843-2:2000(E)iv ISO 2000 All rights reservedForewordISO (the Int
17、ernational Organization for Standardization) is a worldwide federation of national standards bodies (ISOmember bodies). The work of preparing International Standards is normally carried out through ISO technicalcommittees. Each member body interested in a subject for which a technical committee has
18、been established hasthe right to be represented on that committee. International organizations, governmental and non-governmental, inliaison with ISO, also take part in the work. ISO collaborates closely with the International ElectrotechnicalCommission (IEC) on all matters of electrotechnical stand
19、ardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.Publication as an International Standard requires approval by at least
20、75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this part of ISO 11843 may be the subject ofpatent rights. ISO shall not be held responsible for identifying any or all such patent rights.International Standard ISO 11843-2 was prepared by Te
21、chnical Committee ISO/TC 69, Applications of statisticalmethods, Subcommittee SC 6, Measurement methods and results.ISO 11843 consists of the following parts, under the general title Capability of detection:Gbe Part 1: Terms and definitionsGbe Part 2: Methodology in the linear calibration caseAnnex
22、A forms a normative part of this part of ISO 11843. Annexes B and C are for information only.SANS 11843-2This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 11843-2:2000(E) ISO 2000 All rights reserved vIntroductionAn ideal requirement for th
23、e capability of detection with respect to a selected state variable would be that the actualstate of every observed system can be classified with certainty as either equal to or different from its basic state.However, due to systematic and random distortions, this ideal requirement cannot be satisfi
24、ed because:Gbe in reality all reference states, including the basic state, are never known in terms of the state variable. Hence,all states can only be correctly characterized in terms of differences from basic state, i.e. in terms of the netstate variable.In practice, reference states are very ofte
25、n assumed to be known with respect to the state variable. In otherwords, the value of the state variable for the basic state is set to zero; for instance in analytical chemistry, theunknown concentration or the amount of analyte in the blank material usually is assumed to be zero andvalues of the ne
26、t concentration or amount are reported in terms of supposed concentrations or amounts. Inchemical trace analysis especially, it is only possible to estimate concentration or amount differences withrespect to available blank material. In order to prevent erroneous decisions, it is generally recommend
27、ed toreport differences from the basic state only, i.e. data in terms of the net state variable;NOTE In the ISO Guide 30 and in ISO 11095 no distinction is made between the state variable and the net statevariable. As a consequence, in these two documents reference states are, without justification,
28、 assumed to be known withrespect to the state variable.Gbe the calibration and the processes of sampling and preparation add random variation to the measurementresults.In this part of ISO 11843, the following two requirements were chosen:Gbe the probability is G61G20of detecting (erroneously) that a
29、 system is not in the basic state when it is in the basicstate;Gbe the probability is G62G20G20of (erroneously) not detecting that a system, for which the value of the net state variable isequal to the minimum detectable value (xd), is not in the basic state.SANS 11843-2This s tandard may only be us
30、ed and printed by approved subscription and freemailing clients of the SABS .SANS 11843-2This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .INTERNATIONAL STANDARD ISO 11843-2:2000(E) ISO 2000 All rights reserved 1Capability of detection Part 2:M
31、ethodology in the linear calibration case1 ScopeThis part of ISO 11843 specifies basic methods to:Gbe design experiments for the estimation of the critical value of the net state variable, the critical value of theresponse variable and the minimum detectable value of the net state variable,Gbe estim
32、ate these characteristics from experimental data for the cases in which the calibration function is linearand the standard deviation is either constant or linearly related to the net state variable.The methods described in this part of ISO 11843 are applicable to various situations such as checking
33、theexistence of a certain substance in a material, the emission of energy from samples or plants, or the geometricchange in static systems under distortion.Critical values can be derived from an actual measurement series so as to assess the unknown states of systemsincluded in the series, whereas th
34、e minimum detectable value of the net state variable as a characteristic of themeasurement method serves for the selection of appropriate measurement processes. In order to characterize ameasurement process, a laboratory or the measurement method, the minimum detectable value can be stated ifappropr
35、iate data are available for each relevant level, i.e. a measurement series, a measurement process, alaboratory or a measurement method. The minimum detectable values may be different for a measurement series,a measurement process, a laboratory or the measurement method.ISO 11843 is applicable to qua
36、ntities measured on scales that are fundamentally continuous. It is applicable tomeasurement processes and types of measurement equipment where the functional relationship between theexpected value of the response variable and the value of the state variable is described by a calibration function. I
37、fthe response variable or the state variable is a vectorial quantity the methods of ISO 11843 are applicableseparately to the components of the vectors or functions of the components.2 Normative referencesThe following normative documents contain provisions which, through reference in this text, con
38、stitute provisions ofthis part of ISO 11843. For dated references, subsequent amendments to, or revisions of, any of these publicationsdo not apply. However, parties to agreements based on this part of ISO 11843 are encouraged to investigate thepossibility of applying the most recent editions of the
39、 normative documents indicated below. For undatedreferences, the latest edition of the normative document referred to applies. Members of ISO and IEC maintainregisters of currently valid International Standards.ISO 3534-1:1993, Statistics Vocabulary and symbols Part 1: Probability and general statis
40、tical terms.ISO 3534-2:1993, Statistics Vocabulary and symbols Part 2: Statistical quality control.ISO 3534-3:1999, Statistics Vocabulary and symbols Part 3: Design of experiments.SANS 11843-2This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .IS
41、O 11843-2:2000(E)2 ISO 2000 All rights reservedISO 11095:1996, Linear calibration using reference materials.ISO 11843-1:1997, Capability of detection Part 1: Terms and definitions.ISO Guide 30:1992, Terms and definitions used in connection with reference materials.3 Terms and definitionsFor the purp
42、oses of this part of ISO 11843, the terms and definitions of ISO 3534 (all parts), ISO Guide 30,ISO 11095 and ISO 11843-1 apply.4 Experimental design4.1 GeneralThe procedure for determining values of an unknown actual state includes sampling, preparation and themeasurement itself. As every step of t
43、his procedure may produce distortion, it is essential to apply the sameprocedure for characterizing, for use in the preparation and determination of the values of the unknown actualstate, for all reference states and for the basic state used for calibration.For the purpose of determining differences
44、 between the values characterizing one or more unknown actual statesand the basic state, it is necessary to choose an experimental design suited for comparison. The experimental unitsof such an experiment are obtained from the actual states to be measured and all reference states used forcalibration
45、. An ideal design would keep constant all factors known to influence the outcome and control of unknownfactors by providing a randomized order to prepare and perform the measurements.In reality it may be difficult to proceed in such a way, as the preparations and determination of the values of thest
46、ates involved are performed consecutively over a period of time. However, in order to detect major biaseschanging with time, it is strongly recommended to perform one half of the calibration before and one half after themeasurement of the unknown states. However, this is only possible if the size of
47、 the measurement series is knownin advance and if there is sufficient time to follow this approach. If it is not possible to control all influencing factors,conditional statements containing all unproven assumptions shall be presented.Many measurement methods require a chemical or physical treatment
48、 of the sample prior to the measurementitself. Both of these steps of the measurement procedure add variation to the measurement results. If it is requiredto repeat measurements the repetition consists in a full repetition of the preparation and the measurement.However, in many situations the measur
49、ement procedure is not repeated fully, in particular not all of thepreparational steps are repeated for each measurement; see note in 5.2.1.4.2 Choice of reference statesThe range of values of the net state variable spanned by the reference states should includeGbe the value zero of the net state variable, i.e. in analytical chemistry a sample of the blank material, andGbe at least one value close to that suggested by a priori information on the minimum detectable value; if thisrequirement is not fulfilled, the calibration experiment sho
