1、Designation:D277713Standard Practice forDetermination of Precision and Bias of Applicable TestMethods of Committee D19 on Water1This standard is issued under the fixed designation D2777;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision
2、,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice establishes uniform standards for estimat-ing and expressing the precision and bias of applicabl
3、e testmethods for Committee D19 on Water.Statements of precisionand bias in test methods are required by the Form and Style forASTM Standards,“Section A21.Precision and Bias(Manda-tory).”In principle,all test methods are covered by thispractice.1.2 Except as specified in 1.4,1.5,and 1.6,this practic
4、erequires the task group proposing a new test method to carryout a collaborative study from which statements for precision(overall and single-operator standard-deviation estimates)andbias can be developed.This practice provides general guidanceto task groups in planning and conducting such determina
5、tionsof precision and bias.1.3 This practice also provides guidance to task groups forconducting limited-scale collaborative studies(known as“comparability studies”)for test methods that have beenrevised,when such revision includes substantive modifications.Examples of substantive modifications may
6、include,but are notlimited to,changes in mandatory or allowable instrumentation,reagents,reaction times,etc.1.3.1 Changes to applicable water matrices in the Scope ofa method may constitute a substantive modification under thisprovision.However,recognize that even the original collab-orative study m
7、ay not have used all the various matrix typesspecified in the methods original Scope.1.3.2 A methods concentration-range extension that isdeemed to merit additional collaborative testing(even withouta method modification that would otherwise be consideredsubstantive)shall require a full collaborativ
8、e study,as de-scribed in Sections 7.1-7.5,but only at Youden-pair concen-trations representative of the extended range.Note that such acollaborative study could involve as little as a single-sampleYouden-pair study in a single reproducible matrix.1.3.3 Whether a revision to a test method includes su
9、bstan-tive modification shall be determined by consensus of theCommittee.1.4 If a full-scale collaborative study is not technicallyfeasible,due to the nature of the test method or instability ofsamples,the largest feasible scaled-down collaborative studyshall be conducted to provide the best possibl
10、e limited basis forestimating the overall and single-operator standard deviations.1.4.1 Examples of acceptable scaled-down studies are thelocal-area studies conducted by Subcommittee D19.24 onmicrobiological methods because of inherent sample instabil-ity.These studies involve six or more completely
11、 independentlocal-area analysts who can begin analysis of uniform samplesat an agreed upon time.1.4.2 If uniform samples are not feasible under anycircumstances,a statement of single-operator precision willmeet the requirements of this practice.Whenever possible,thisstatement should be developed fro
12、m data generated by inde-pendent multiple operators,each doing replicate analyses onindependent samples(of a specific matrix type),which gener-ally fall within specified concentration ranges(see 7.2.5.2(3).1.4.3 This practice is not applicable to methodology involv-ing continuous sampling or continu
13、ous measurement,or both,of specific constituents and properties.1.4.4 This practice is also not applicable to open-channelflow measurements.1.5 A collaborative study that satisfied the requirements ofthe version of this practice in force when the study wasconducted will continue to be considered an
14、adequate basis forthe precision-and-bias statement required in each test method.If the study does not satisfy the current minimum requirementsfor a collaborative study,a statement listing the studysdeficiencies and a reference to this paragraph shall be includedin the precision-and-bias statement as
15、 the basis for an exemp-tion from the current requirements.1.6 This paragraph relates to special exemptions not clearlyacceptable under 1.4 or 1.5.With the approval of CommitteeD19 on the recommendation of the Results Advisor and theTechnical Operations Section of the Executive Subcommitteeof Commit
16、tee D19,a statement giving a compelling reasonwhy compliance with all or specific points of this practice1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.02 on Quality Systems,Specification,and Statistics.Current edition approved Jan.1,2013.Published February 2013.Originallyapproved in 1969.Last previous edition approved in 2012 as D2777 12.DOI:10.1520/D2777-13.Copyright ASTM International,100 Barr Harbor Drive,PO Box C70
