ASTM_D_4697_-_95_2001.pdf

Designation:D 4697 95(Reapproved 2001)Standard Guide forMaintaining Test Methods in the Users Laboratory1This standard is issued under the fixed designation D 4697;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide is intended to assist laboratories in maintain-ing precision and controlling bias in testing.It includesstatistical procedures for detecting lack of control,changes incalibration constants,and in operator technique.Suggestionsare given for the correction of some out of control situations.1.2 This guide includes the following topics:Topic TitleSectionNumberScope1Referenced Documents2Terminology3Significance and Use4Calibration Control5Test Performance Control6Annexes:Calibration ControlAnnex A1Test Performance ControlAnnex A21.3 This standard does not give all of the details forpreparing statistical quality control charts or the statistical testsused to interpret them,but such information may be foundeasily in a number of publications.22.Referenced Documents2.1 ASTM Standards:D 123 Terminology Relating to Textiles3D 1578 Test Method for Breaking Strength of Yarn in SkeinForm3E 456 Terminology Relating to Quality and Statistics42.2 ASTM Adjuncts:TEX-PAC5NOTE1Tex-Pac is a group of PC programs on floppy disks,availablethrough ASTM Headquarters,100 Barr Harbor Drive,Conshohocken,PA19428,USA.The control chart parameters described in the annexes of thisguide can be calculated with one of these programs and the control chartsscreen plotted.3.Terminology3.1 Definitions:3.1.1 accuracy,nof a test method,the degree of agree-ment between the true value of the property being tested(or anaccepted standard value)and the average of many observationsmade according to the test method,preferably by manyobservers.(See also bias and precision.)3.1.2 attribute data,nobserved values or determinationswhich indicate the presence or absence of specific character-istics.3.1.3 bias,nin statistics,a constant or systematic error intest results.3.1.3.1 DiscussionBias can exist between the true valueand a test result obtained from one method;between test resultsfrom two methods;or between two test results obtained from asingle method,for example,between operators or betweenlaboratories.3.1.4 calibrate,vtto determine and record the relationshipbetween a set of standard units of measure and the output of aninstrument or test procedure.3.1.5 calibration,nthe act or process of calibrating;therecorded relationship resulting from calibrating.3.1.6 measurement value,nthe numerical result of quan-tifying a particular property or dimension.(Syn.measurement,measurement datum.)3.1.7 moving range,MR,nthe difference without regardto sign between two successive observations.3.1.8 precision,nthe degree of agreement within a set ofobservations or test results obtained as directed in a testmethod.3.1.8.1 DiscussionThe term“precision”delimited in vari-ous ways is used to describe different aspects of precision.Thisusage was chosen in preference to the use of“repeatability”and“reproducibility”which have been assigned conflictingmeanings by various authors and standardizing bodies.3.1.9 test method,na definitive procedure for the identi-fication,measurement,and evaluation of one or more qualities,characteristics,or properties of a material,product,system,orservice that produces a test result.3.1.10 verification,nthe act or process of verifying.3.1.11 verify,vt(1)to determine whether a previouslycalibrated instrument,standard solution,or other standard is1This guide is under the jurisdiction of ASTM Committee D13 on Textiles andis the direct responsibility of Subcommittee D13.93 on Statistics.Current edition approved May 15,1995.Published July 1995.Originallypublished as D 4697 87.Last previous edition D 4697 91.2For information see:Juran,J.M.,ed.,Quality Control Handbook,McGrawHill,New York,4th ed.,1988;Manual on Presentation of Data and Control ChartAnalysis,ASTM STP 15D,ASTM,1976;and Statistical Quality Control Handbook,Western Electric Co.,Inc.,2nd ed.,1985(Inquiries may be made to:AT&TTechnologies,Commercial Sales Clerk,Select Code 700-444,P.O.Box 19901,Indianapolis,IN 44219).3Annual Book of ASTM Standards,Vol 07.01.4Annual Book of ASTM Standards,Vol 14.02.5PC programs on floppy disks are available through ASTM.For a 312inch diskrequest PCN:12-429040-18,for a 514inch disk request PCN:12-429041-18.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.still properly calibrated;(2)to establish that an operation hasbeen completed correctly.3.1.12 For definitions of textile terms in this standard,referto Terminology D 123.For definitions of statistical terms inthis standard,refer to Terminology D 123 or TerminologyE 456.3.2 Definitions of Terms Specific to Thi