Designation:C670−15StandardPracticeforPreparingPrecisionandBiasStatementsforTestMethodsforConstructionMaterials1ThisstandardisissuedunderthefixeddesignationC670;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1TheFormandStyleforASTMStandardsrequiresthatalltestmethodscontainstatementsonprecisionandbias.Further,theprecisionstatementisrequiredtocontainastatementonsingle-operatorprecision(repeatability)andastatementonmultilaboratoryprecision(reproducibility).Thispracticeprovidesguidanceforpreparingprecisionandbiasstatementsthatcomplywiththeserequirements.Discussionofthepurposeandsignificanceofprecisionandbiasstatementsforusersoftestmethodsisalsoprovided.ExamplesofprecisionstatementsthatconformtothispracticeareincludedinAppendixX1.ThispracticesupplementsPracticeE177andhasbeendevelopedtomeettheneedsofASTMCommitteesdealingwithconstructionmaterials.NOTE1—AlthoughthispracticeisunderthejurisdictionofCommitteeC09,thecurrentversionwasdevelopedjointlybyCommitteesC01andC09andhassubsequentlybeenadoptedforusebyothercommitteesdealingwithconstructionmaterials.1.2Thispracticeassumesthataninterlaboratorystudy(ILS)hasbeencompletedinaccordancewithPracticeC802orPracticeE691.Theinterlaboratorystudyprovidestheneces-sarystatisticalvaluestowritetheprecisionandbiasstate-ments.1.3Thesystemofunitsforthispracticeisnotspecified.Dimensionalquantitiesinthepracticearepresentedonlyinexamplesofprecisionandbiasstatements.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2C802PracticeforC...
