Designation:E2480−12StandardPracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethodwithMulti-ValuedMeasurands1ThisstandardisissuedunderthefixeddesignationE2480;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticedescribesthetechniquesforplanning,conducting,andanalyzingtheresultsofaninterlaboratorystudy(ILS)conductedforcertaintestmethodswithinCom-mitteeE12.1.2Thispracticedoesnotconcernitselfwiththedevelop-mentofthetestmethodbutratherwiththegatheringoftheinformationneededfortheprecisionandbiasstatementafterthecompletionofdevelopmentofthetestmethod.ThedataobtainedintheILSmayindicate,however,thatfurthereffortisneededtoimprovethetestmethod.1.3Thispracticeisconcernedexclusivelywithtestmethodsthatderiveamulti-valuedmeasurand,suchas,butnotlimitedto,spectralreflectance,transmittancefunction,tristimulusvalues,orRGBvalues.Variationinmeasurementsofsuchmulti-valuedmeasurandsareusuallyanalyzedbyreducingthedatatoasingle-valuedparameter,suchascolordifference,∆E.1.4Thispracticecoversmethodsofdealingwiththenon-normaldistributionofthevariationofsetsofcolor-differences.Thisisdonesothattheusermayderivevalidstatisticsfromsuchnon-normaldistributions.1.5Thispracticedoesnotcovertestmethods,eveninCommitteeE12,whosemeasurandsaresingle-valued,orwhosevariationsareknowntobenormallydistributed.TaskgroupsinvolvedwithsuchtestmethodsarereferredtoPracticeE691whichcontainspreferablemethodsofanalyzingdatawiththoseproperties.1.6Thispracticeisnotintendedtoestablishamethodforestimatingpossiblecolor-differencetolerances.1.7ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.1.8Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardto...
