ASTM_C_670_-_15.pdf

Designation:C67015Standard Practice forPreparing Precision and Bias Statements for Test Methodsfor Construction Materials1This standard is issued under the fixed designation C670;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()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 The Form and Style for ASTM Standards requires thatall test methods contain statements on precision and bias.Further,the precision statement is required to contain astatement on single-operator precision(repeatability)and astatement on multilaboratory precision(reproducibility).Thispractice provides guidance for preparing precision and biasstatements that comply with these requirements.Discussion ofthe purpose and significance of precision and bias statementsfor users of test methods is also provided.Examples ofprecision statements that conform to this practice are includedin Appendix X1.This practice supplements Practice E177 andhas been developed to meet the needs of ASTM Committeesdealing with construction materials.NOTE1Although this practice is under the jurisdiction of CommitteeC09,the current version was developed jointly by Committees C01 andC09 and has subsequently been adopted for use by other committeesdealing with construction materials.1.2 This practice assumes that an interlaboratory study(ILS)has been completed in accordance with Practice C802 orPractice E691.The interlaboratory study provides the neces-sary statistical values to write the precision and bias state-ments.1.3 The system of units for this practice is not specified.Dimensional quantities in the practice are presented only inexamples of precision and bias statements.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C802 Practice for Conducting an Interlaboratory Test Pro-gram to Determine the Precision of Test Methods forConstruction MaterialsC1067 Practice for Conducting a Ruggedness Evaluation orScreening Program for Test Methods for ConstructionMaterialsD6607 Practice for Inclusion of Precision Statement Varia-tion in Specification LimitsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 For definitions of general statistical terms,refer toTerminology E456.3.2 Definitions of Terms Specific to This Standard:33.2.1 test determination,nthe value of a characteristic ofa single test specimen obtained by a specified test method.3.2.1.1 DiscussionThe term replicate is often used for atest determination.3.2.2 test result,nthe value of a characteristic of amaterial obtained by carrying out a specified test method.3.2.2.1 DiscussionA test result may be a single testdetermination or the average of a specified number of testdeterminations,or replicates(see 4.1 for additional discussion).3.2.3 identical test specimens,ntest specimens selected atrandom and made from a single quantity or batch of materialthat is as homogeneous as possible.1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand Concrete Aggregates and is the direct responsibility of Subcommittee C09.94on Evaluation of Data(Joint C09 and C01).Current edition approved June 15,2015.Published August 2015.Originallyapproved in 1971.Last previous edition approved in 2013 as C670 13.DOI:10.1520/C0670-15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Terms are listed in order of hierarchy beginning with the basic concept.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.3.1 DiscussionIn interlaboratory studies of test meth-ods for fresh cementitious mixtures,a practicable approach forobtaining identical tests specimens is to assemble techniciansfrom different laboratories at one location and test specimensare made from the same batch of the fresh mixture.Forinterlaboratory studies of nondestructive test methods,thesame test specimens can be circulated among participatinglaboratories,provided the characteristic of interest does notchange during the time to complete the study.3.2.4 single-operator standard deviation,sr,(or coef