AP统计学讲义培训课件.ppt

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1、统计学精讲精练主讲老师：黄逸昆2004APSTATISTICSFREE-RESPONSEQUESTIONS(FORMB)STATISTICSSECTIONⅡPartAQuestions1-5Spendabout65minutesonthispartoftheexam.PercentofSectionIIgrade—75(a)Describethenatureoftherelationshipbetweenimpactrateandage.Priortofittingalinearregressionmodel,theresearcherstransformed

2、bothimpactrateandagebyusinglogarithms.Thefollowingcomputeroutputandresidualplotwereproduced.(b)Interpretthevalueofr2.(c)Commentontheappropriatenessofthislinearregressionformodelingtherelationshipbetweenthetransformedvariables.2Atacertainuniversity,studentswholiveinthedormitorieseata

3、tacommondininghall.Recently,somestudentshavebeencomplainingaboutthequalityofthefoodservedthere.Thedininghallmanagerdecidedtodoasurveytoestimatetheproportionofstudentslivinginthedormitorieswhothinkthatthequalityofthefoodshouldbeimproved.Oneevening,themanageraskedthefirst100studentsen

4、teringthedininghalltoanswerthefollowingquestion.(a)Inthissetting,explainhowbiasmayhavebeenintroducedbasedonthewaythisconveniencesamplewasselectedandsuggesthowthesamplecouldhavebeenselecteddifferentlytoavoidthatbias.(b)Inthissetting,explainhowbiasmayhavebeenintroducedbasedonthewaythe

5、questionwaswordedandsuggesthowitcouldhavebeenwordeddifferentlytoavoidthatbias.TrainscarrybauxiteorefromamineinCanadatoanaluminumprocessingplantinnorthernNewYorkstateinhoppercars.Fillingequipmentisusedtoloadoreintothehoppercars.Whenfunctioningproperly,theactualweightsoforeloadedintoe

6、achcarbythefillingequipmentatthemineareapproximatelynormallydistributedwithameanof70tonsandastandarddeviationof0.9ton.Ifthemeanisgreaterthan70tons,theloadingmechanismisoverfilling.(a)Ifthefillingequipmentisfunctioningproperly,whatistheprobabilitythattheweightoftheoreinarandomlyselec

7、tedcarwillbe70.7tonsormore?Showyourwork.(b)Supposethattheweightoforeinarandomlyselectedcaris70.7tons.Wouldthatfactmakeyoususpectthattheloadingmechanismisoverfillingthecars?Justifyyouranswer.(c)Ifthefillingequipmentisfunctioningproperly,whatistheprobabilitythatarandomsampleof10carswi

8、llhaveameanoreweigh