Designation:E3076−18StandardPracticeforDeterminationoftheSlopeintheLinearRegionofaTestRecord1ThisstandardisissuedunderthefixeddesignationE3076;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticepresentsanautomated,objectivelinear-fittingmethodfordeterminingtheslopeofthelinearportionofatestrecord.Themethodassumesthatthereisalinearregionearlyinthetestrecordwherethevalueoftheyvariableincreasesroughlyinproportiontothexvariableandtheslopeoftherecorddecreasesafterthelinearregion.Thepracticedeterminesthebestlinearfittothedatabasedontheleastnormalizedresidualandprovidesmetricsforevaluatingthequalityofthetestrecordandthequalityoftheresultantfit.1.2Dataqualitymetricsareappliedthatevaluatethelevelofnoiseandthedigitalresolutionofthedatatodetermineifthetestrecordisadequateforalinearregressionanalysis.Fitqualitymetricsuseanalysisofresidualsinthevicinityofthefitrangetodetermineifthetestrecordisadequatelylinearandthefitrangeissufficientlylarge.1.3Fortestrecordsthatmeetthedataandfitqualitymetrics,thepracticedeterminesarepeatableslopewithouttheneedforoperatorinputthatisindependentofoperatorjudgment.Fortestrecordsthatfailoneormoreofthequalitymetrics,itisrecommendedthattheanalystevaluatethefittodetermineifitisacceptable.1.4Thispracticerepresentsageneralpurposeapproachthatisapplicableforanyteststandardormethodinwhichalinearfitisdesired.Itisintendedthatthispracticecanbecalleduponbystandardtestmethodswhenslopemustbedetermined.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.6Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedpr...
