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【英文标准名称】:StandardTestMethodforDirectionalDifferenceTest
【原文标准名称】:定向差测试的标准试验方法
【标准号】:ASTME2164-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:E18.04
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:2-AFC(alternativeforced-choice)test;Assessment/Assesors;Directionaldifferencetest;Pairedcomparisontest;Perceivabledifferences;Sensoryanalysis
【摘要】:Thedirectionaldifferencetestdetermineswithagivenconfidencelevelwhetherornotthereisaperceivabledifferenceintheintensityofaspecifiedattributebetweentwosamples,forexample,whenachangeismadeinaningredient,aprocess,packaging,handling,orstorage.Thedirectionaldifferencetestisinappropriatewhenevaluatingproductswithsensorycharacteristicsthatarenoteasilyspecified,notcommonlyunderstood,ornotknowninadvance.Otherdifferencetestmethodssuchasthesame-differenttestshouldbeused.Aresultofnosignificantdifferenceinaspecificattributedoesnotensurethattherearenodifferencesbetweenthetwosamplesinotherattributesorcharacteristics,nordoesitindicatethattheattributeisthesameforbothsamples.Itmaymerelyindicatethatthedegreeofdifferenceistoolowtobedetectedwiththesensitivity(x03B1;,x03B2;,andPmax)chosenforthetest.Themethoditselfdoesnotchangewhetherthepurposeofthetestistodeterminethattwosamplesareperceivablydifferentversusthatthesamplesarenotperceivablydifferent.OnlytheselectedvaluesofPmax,x03B1;,andx03B2;change.Iftheobjectiveofthetestistodetermineifthetwosamplesareperceivablydifferent,thenthevalueselectedforx03B1;istypicallysmallerthanthevalueselectedforx03B2;.Iftheobjectiveistodetermineifnoperceivabledifferenceexists,thenthevalueselectedforx03B2;istypicallysmallerthanthevalueselectedforx03B1;andthevalueofPmaxneedstobestatedexplicitly.1.1Thistestmethodcoversaprocedureforcomparingtwoproductsusingatwo-alternativeforced-choicetask.1.2Thismethodissometimesreferredtoasapairedcomparisontestorasa2-AFC(alternativeforcedchoice)test.1.3Adirectionaldifferencetestdetermineswhetheradifferenceexistsintheperceivedintensityofaspecifiedsensoryattributebetweentwosamples.1.4Directionaldifferencetestingislimitedinitsapplicationtoaspecifiedsensoryattributeanddoesnotdirectlydeterminethemagnitudeofthedifferenceforthatspecificattribute.Assessorsmustbeabletorecognizeandunderstandthespecifiedattribute.Alackofdifferenceinthespecifiedattributedoesnotimplythatnooveralldifferenceexists.1.5Thistestmethoddoesnotaddresspreference.1.6Adirectionaldifferencetestisasimpletaskforassessors,andisusedwhensensoryfatigueorcarryoverisaconcern.Thedirectionaldifferencetestdoesnotexhibitthesameleveloffatigue,carryover,oradaptationasmultiplesampletestssuchastriangleorduo-triotests.Fordetailoncomparisonsamongthevariousdifferencetests,seeEnnis(1),MacRae(2),andO''MahonyandOdbert(3).1.7Theprocedureofthetestdescribedinthisdocumentconsistsofpresentingasinglepairofsamplestotheassessors.1.8Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:A20
【国际标准分类号】:19_020
【页数】:11P.;A4
【正文语种】:英语