Designation:E2165–01StandardPracticeforEstablishinganUncertaintyBudgetfortheChemicalAnalysisofMetals,Ores,andRelatedMaterials1ThisstandardisissuedunderthefixeddesignationE2165;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1ThispracticedescribesamodelforestablishingISO17025-compliantuncertaintybudgetsforthechemicalanalysisofmetals,ores,andrelatedmaterials.ItisbasedonapplyingtheHorwitz2functiontowidelyaccepted,diverseinterlabora-torytestprograms,suchasinterlaboratorytestingofstandardtestmethodsandproficiencytestingprograms.Thisfunctionexpressestheinterlaboratorystandarddeviationsthatcanbeexpectedforanyconcentrationlevelascompetentlaboratoriesuseoptimizedtestprocedurestoanalyzeanymatrixforanyanalyte.Itmaybeusedtosetaimuncertaintiesagainstwhichtoplannewstandardtestmethodsandtoassesstheperfor-manceofexistingtestmethods.1.2Anoptimizedtestprocedureisoneinwhichthefinaltestresultsareatleastequivalenttoalternative,state-of-the-artprocedures.Intheanalyticalchemistrycommunity,thismeansthatcalibrationsarecarriedout,verified,andcontrolledsuchthatthefinaltestresultshavenosystematic,detectablebias.Theeliminationofsourcesofbiasisakeyresponsibilityofanypersonwhodesignsanalyticaltestmethods.Hence,ananalyti-caltestmethodthatcontainssystematic,measurablesourcesofbiaswouldprobablynotbeacceptedasanASTMtestmethodanditsperformancedatawouldprobablynotbeincompliancewiththeproceduresdescribedinthispractice.1.3Theuncertaintybudgetmodeldescribedinthispracticeisbasedontheassumptionthat,inanormallydistributed,bias-freeenvironment,measurementuncertaintywillimprovebythesquarerootoftwowitheachremovalofasignificantsourceofvariation.Conversely,itisassumedthatmeasure-mentuncertaintywillworsenbythesameamountwitheachadditionofasignificantsourceofvariation.Furthermore,thismodelassumestha...
