Designation:D6250−98(Reapproved2009)StandardPracticeforDerivationofDecisionPointandConfidenceLimitforStatisticalTestingofMeanConcentrationinWasteManagementDecisions1ThisstandardisissuedunderthefixeddesignationD6250;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversalogicalbasisforthederivationofadecisionpointandconfidencelimitwhenmeanconcentrationisusedformakingenvironmentalwastemanagementdeci-sions.Thedeterminationofadecisionpointorconfidencelimitshouldbemadeinthecontextofthedefinedproblem.Themainfocusofthispracticeisonthedeterminationofadecisionpoint.1.2Inenvironmentalmanagementdecisions,thederivationofadecisionpointallowsadirectcomparisonofasamplemeanagainstthisdecisionpoint,wheresimilardecisionscanbemadebycomparingaconfidencelimitagainstaconcentra-tionlimit(forexample,aregulatorylimit,whichwillbeusedasasurrogatetermforanyconcentrationlimitthroughoutthispractice).Thispracticefocusesonmakingenvironmentaldecisionsusingthiskindofstatisticalcomparison.Otherfactors,suchasanyqualitativeinformationthatmaybeimportanttodecision-making,arenotconsideredhere.1.3Adecisionpointisaconcentrationlevelstatisticallyderivedbasedonaspecifieddecisionerrorandisusedinadecisionruleforthepurposeofchoosingbetweenalternativeactions.1.4Thispracticederivesthedecisionpointandconfidencelimitintheframeworkofastatisticaltestofhypothesisunderthreedifferentpresumptions.Therelationshipbetweendeci-sionpointandconfidencelimitisalsodescribed.1.5Determinationofdecisionpointsandconfidencelimitsforstatisticsotherthanmeanconcentrationisnotcoveredinthispractice.Thispracticealsoassumesthatthedataarenormallydistributed.Whenthisassumptiondoesnotapply,atransformationtonormalizethedatamaybeneeded.Ifotherstatisticaltestssuchasnonparametricmethodsareusedinthedecisionrule,thisprac...
