SANS 5725-5-2009 Accuracy (trueness and precision) of measurement methods and results Part 5 Alternative methods for the determination of the precision of a standard measurement me.pdf

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 978-0-626-23189-7 SANS 5725-5:2009Edition 1 and ISO tech. corr. 1ISO 5725-5:1998Edition 1 and tech. corr. 1SOUTH AFRICAN NATIONAL STANDARD Accuracy

4、(trueness and precision) of measurement methods and results Part 5: Alternative methods for the determination of the precision of a standard measurement method This national standard is the identical implementation of ISO 5725-5:1998 and ISO technical corrigendum 1, and is adopted with the permissio

5、n of the International Organization for Standardization. Published by SABS Standards Division 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 5725-5:2009 Edition 1 and ISO tech. corr. 1 ISO 5725-5:1998 Edition 1 and tech.

6、corr. 1 Table of changes Change No. Date Scope ISO tech. corr. 1 2005 Corrected to replace equations (25) and (26) in subclause 5.4.2 and equation (72) in subclause 6.4.3. National foreword This South African standard was approved by National Committee SABS TC 169, Applications of statistical method

7、s, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in September 2009. ICS 03.120.30; 17.020 Ref. No. ISO 5725-5:1998/Cor.1:2005(E) ISO 2005 All rights reserved Published in Switzerland INTERNATIONAL S

8、TANDARD ISO 5725-5:1998 TECHNICAL CORRIGENDUM 1 Published 2005-08-15 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATIONAccuracy (trueness and precision) of measurement methods and results Part 5: Alternative methods for the determination of the precision of a

9、 standard measurement method TECHNICAL CORRIGENDUM 1 Exactitude (justesse et fidlit) des rsultats et mthodes de mesure Partie 5: Mthodes alternatives pour la dtermination de la fidlit dune mthode de mesure normalise RECTIFICATIF TECHNIQUE 1 Technical Corrigendum 1 to ISO 5725-5:1998 was prepared by

10、Technical Committee ISO/TC 69, Applications of statistical methods, Subcommittee SC 6, Measurement methods and results. Page 17, Equations (25) and (26) in Subclause 5.4.2 Replace 1qjijjyyp=with 1qjijiyyp=in Equation (25). Replace ()()211qyj ij jjsyyp= with ()()211qyj ij jisyyp= in Equation (26). Pa

11、ge 38, Equation (72) in Subclause 6.4.3 Replace ()22L drs ssn= with ( )22L drs ssn= . SANS 5725-5:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .SANS 5725-5:2009This standard may only be used and printed by approved subscription and free

12、mailing clients of the SABS .AReference numberISO 5725-5:1998(E)INTERNATIONALSTANDARDISO5725-5First edition1998-07-15Accuracy (trueness and precision) ofmeasurement methods and results Part 5:Alternative methods for the determination ofthe precision of a standard measurementmethodExactitude (justess

13、e et fidlit) des rsultats et mthodes de mesure Partie 5: Mthodes alternatives pour la dtermination de la fidlit dunemthode de mesure normaliseSANS 5725-5:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5725-5:1998(E) ISO 1998All right

14、s reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronicor mechanical, including photocopying and microfilm, without permission in writing from the publisher.International Organization for StandardizationCase postale 56

15、 CH-1211 Genve 20 SwitzerlandInternet isoiso.chPrinted in SwitzerlandiiContents Page1 Scope . 12 Normative references 13 Definitions 24 Split-level design 24.1 Applications of the split-level design 24.2 Layout of the split-level design 24.3 Organization of a split-level experiment 34.4 Statistical

16、model 44.5 Statistical analysis of the data from a split-level experiment . 54.6 Scrutiny of the data for consistency and outliers . 64.7 Reporting the results of a split-level experiment 74.8 Example 1: A split-level experiment Determination of protein 75 A design for a heterogeneous material 135.1

17、 Applications of the design for a heterogeneous material . 135.2 Layout of the design for a heterogeneous material . 145.3 Organization of an experiment with a heterogeneous material . 155.4 Statistical model for an experiment with a heterogeneous material 165.5 Statistical analysis of the data from

18、 an experiment with a heterogeneous material 175.6 Scrutiny of the data for consistency and outliers . 205.7 Reporting the results of an experiment on a heterogeneous material . 215.8 Example 2: An experiment on a heterogeneous material 215.9 General formulae for calculations with the design for a h

19、eterogeneous material 295.10 Example 3: An application of the general formulae . 306 Robust methods for data analysis . 336.1 Applications of robust methods of data analysis . 336.2 Robust analysis: Algorithm A . 356.3 Robust analysis: Algorithm S . 366.4 Formulae: Robust analysis for a particular l

20、evel of a uniform-level design . 386.5 Example 4: Robust analysis for a particular level of a uniform-level design . 386.6 Formulae: Robust analysis for a particular level of a split-level design . 426.7 Example 5: Robust analysis for a particular level of a split-level design . 426.8 Formulae: Robu

21、st analysis for a particular level of an experiment on a heterogeneous material . 456.9 Example 6: Robust analysis for a particular level of an experiment on a heterogeneous material . 45AnnexesA (normative) Symbols and abbreviations used in ISO 5725 50B (informative) Derivation of the factors used

22、in algorithms A and S 53C (informative) Derivation of equations used for robust analysis 55D (informative) Bibliography . 56SANS 5725-5:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS . ISO ISO 5725-5:1998(E)iiiForewordISO (the Internation

23、al Organization for Standardization) is a world-wide 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 been es

24、tablished hasthe right to be represented on that committee. International organisations, 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 standardizat

25、ion.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 75 % of the member bodies casting a vote.ISO 5725-5 was prepared by Technical Committee ISO/TC 69, Applications

26、of statistical methods, SubcommitteeSC 6, Measurement methods and results.ISO 5725 consists of the following parts, under the general title Accuracy (trueness and precision) of measurementmethods and results: Part 1: General principles and definitions Part 2: Basic method for the determination of re

27、peatability and reproducibility of a standard measurementmethod Part 3: Intermediate measures of the precision of a standard measurement method Part 4: Basic methods for the determination of the trueness of a standard measurement method Part 5: Alternative methods for the determination of the precis

28、ion of a standard measurement method Part 6: Use in practice of accuracy valuesParts 1 to 6 of ISO 5725 together cancel and replace ISO 5725:1986, which has been extended to cover trueness(in addition to precision) and intermediate precision conditions (in addition to repeatability conditions andrep

29、roducibility conditions).Annex A forms an integral part of this part of ISO 5725. Annexes B, C and D are for information only.SANS 5725-5:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5725-5:1998(E) ISOivIntroduction0.1 This part of

30、 ISO 5725 uses two terms trueness and precision to describe the accuracy of a measurementmethod. Trueness refers to the closeness of agreement between the average value of a large number of test resultsand the true or accepted reference value. Precision refers to the closeness of agreement between t

31、est results.0.2 General consideration of these quantities is given in ISO 5725-1 and so is not repeated here. This part ofISO 5725 should be read in conjunction with ISO 5725-1 because the underlying definitions and general principlesare given there.0.3 ISO 5725-2 is concerned with estimating, by me

32、ans of interlaboratory experiments, standard measures ofprecision, namely the repeatability standard deviation and the reproducibility standard deviation. It gives a basicmethod for doing this using the uniform-level design. This part of ISO 5725 describes alternative methods to thisbasic method.a)

33、With the basic method there is a risk that an operator may allow the result of a measurement on one sample toinfluence the result of a subsequent measurement on another sample of the same material, causing theestimates of the repeatability and reproducibility standard deviations to be biased. When t

34、his risk is consideredto be serious, the split-level design described in this part of ISO 5725 may be preferred as it reduces this risk.b) The basic method requires the preparation of a number of identical samples of the material for use in theexperiment. With heterogeneous materials this may not be

35、 possible, so that the use of the basic method thengives estimates of the reproducibility standard deviation that are inflated by the variation between the samples.The design for a heterogeneous material given in this part of ISO 5725 yields information about the variabilitybetween samples which is

36、not obtainable from the basic method; it may be used to calculate an estimate ofreproducibility from which the between-sample variation has been removed.c) The basic method requires tests for outliers to be used to identify data that should be excluded from thecalculation of the repeatability and re

37、producibility standard deviations. Excluding outliers can sometimes have alarge effect on the estimates of repeatability and reproducibility standard deviations, but in practice, whenapplying the outlier tests, the data analyst may have to use judgement to decide which data to exclude. Thispart of I

38、SO 5725 describes robust methods of data analysis that may be used to calculate repeatability andreproducibility standard deviations from data containing outliers without using tests for outliers to exclude data,so that the results are no longer affected by the data analysts judgement.SANS 5725-5:20

39、09This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .INTERNATIONAL STANDARD ISO ISO 5725-5:1998(E)1Accuracy (trueness and precision) of measurement methods andresults Part 5:Alternative methods for the determination of the precision of a standar

40、dmeasurement method1 ScopeThis part of ISO 5725 provides detailed descriptions of alternatives to the basic method for determining the repeatability andreproducibility standard deviations of a standard measurement method, namely the split-level design and adesign for heterogeneous materials; describ

41、es the use of robust methods for analysing the results of precision experiments without using outliertests to exclude data from the calculations, and in particular, the detailed use of one such method.This part of ISO 5725 complements ISO 5725-2 by providing alternative designs that may be of more v

42、alue in somesituations than the basic design given in ISO 5725-2, and by providing a robust method of analysis that givesestimates of the repeatability and reproducibility standard deviations that are less dependent on the data analystsjudgement than those given by the methods described in ISO 5725-

43、2.2 Normative referencesThe following standards contain provisions which, through reference in this text, constitute provisions of this part ofISO 5725. At the time of publication, the editions indicated were valid. All standards are subject to revision, andparties to agreements based on this part o

44、f ISO 5725 are encouraged to investigate the possibility of applying themost recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently validInternational Standards.ISO 3534-1:1993, Statistics Vocabulary and symbols Part 1: Probability and general statis

45、tical terms.ISO 3534-3:1985, Statistics Vocabulary and symbols Part 3: Design of experiments.ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part 1: Generalprinciples and definitions.ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and r

46、esults Part 2: Basic methodfor the determination of repeatability and reproducibility of a standard measurement method.SANS 5725-5:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5725-5:1998(E) ISO23 DefinitionsFor the purposes of thi

47、s part of ISO 5725, the definitions given in ISO 3534-1 and in ISO 5725-1 apply.The symbols used in ISO 5725 are given in annex A.4 Split-level design4.1 Applications of the split-level design4.1.1 The uniform level design described in ISO 5725-2 requires two or more identical samples of a material

48、to betested in each participating laboratory and at each level of the experiment. With this design there is a risk that anoperator may allow the result of a measurement on one sample to influence the result of a subsequentmeasurement on another sample of the same material. If this happens, the resul

49、ts of the precision experiment willbe distorted: estimates of the repeatability standard deviation srwill be decreased and estimates of the between-laboratory standard deviation sLwill be increased. In the split-level design, each participating laboratory is providedwith a sample of each of two similar materials, at each level of the experiment, and the operators are told that thesamples are not identical, but they are not told by how much the materi