12_Equivalence(1)

12_Equivalence(1) - EquivalenceofmodelcomparisonandCbFtests

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Unformatted text preview: EquivalenceofmodelcomparisonandCbFtests ContinuationoftheStoragetimeexamplefromPart9.Data: StorageTemperature StorageTime 20 C 3 C 3months 25 91215 6months 6677 16 Copyright c 2011Dept.ofStatistics(IowaStateUniversity) Statistics511 1/1 SummaryofresultsfromCbestimatesandtests Quantity Estimate Fstatpvalue Timemaineffect 3.5 6.00 0.049 Tempmaineffect 9.0 39.71 0.00074 Interaction 1.0 0.12 0.74 Thesecorrespondtotestsof: TimeHo: 3 , 20 + 3 , 30 = 6 , 20 + 6 , 30 TempHo: 3 , 20 + 6 , 20 = 3 , 30 + 6 , 30 InteractionHo: 3 , 20 3 , 30 = 6 , 20 6 , 30 NoquestionabouttheseHo. Copyright c 2011Dept.ofStatistics(IowaStateUniversity) Statistics511 2/1 Modelcomparisons IfyoufittwospecificmodelsandcompareresidualSS, noquestionwhatmodelsbeingcompared. Interaction: InR:lm(y time+temp+time:temp)SSE=23.50with6d.f. lm(y time+temp) SSE=23.98with7d.f. InSAS:modely=timetemptime*temp;SSE=23.50with6d.f. modely=timetemp; SSE=23.98with7d.f. F = ( 23 . 98 23 . 50 ) / ( 7 6 ) 23 . 50 / 6 = . 48 / 3 . 917 = . 122 SameasCbtest Copyright c 2011Dept.ofStatistics(IowaStateUniversity) Statistics511 3/1 Modelcomparisons Timemaineffect: InR:lm(y time+temp+time:temp)SSE=23.50with6d.f. lm(y temp+time:temp) SSE=23.50with6d.f. InSAS:modely=timetemptime*temp;SSE=23.50with6d.f. modely=temptime*temp; SSE=23.50with6d.f. Weseemtohavefitthesamemodeleachtime Clueismodelmatrixassociatedwithlm(y...
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This note was uploaded on 02/11/2012 for the course STAT 511 taught by Professor Staff during the Spring '08 term at Iowa State.

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12_Equivalence(1) - EquivalenceofmodelcomparisonandCbFtests

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