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Copyright©2009CengageLearning1.1ChapterOneWhatisStatistics?Copyright©2009CengageLearning1.2WhatisStatistics?“Statisticsisawaytogetinformationfromdata.”Copyright©2009CengageLearning1.3WhatisStatistics?“Statisticsisawaytogetinformationfromdata”DataStatisticsInformationDefinitions:OxfordEnglishDictionaryStatisticsisatoolforcreatingnewunderstandingfromasetofnumbers.Copyright©2009CengageLearning1.4Example2.6StatsAnxietyAstudentenrolledinabusinessprogramisattendingthefirstclassoftherequiredstatisticscourse.Thestudentissomewhatapprehensivebecausehebelievesthemyththatthecourseisdifficult.Toalleviatehisanxietythestudentaskstheprofessoraboutlastyear’smarks.Theprofessorobligesandprovidesalistofthefinalmarks,whichiscomposedoftermworkplusthefinalexam.Whatinformationcanthestudentobtainfromthelist?Copyright©2009CengageLearning1.5Example2.6StatsAnxiety658172597153856666707271797677686573647282737775808589748683877767807869646779606278599274686369676784697262747368837465Copyright©2009CengageLearning1.6Example2.6StatsAnxiety“Typicalmark”Mean(averagemark)Median(marksuchthat50%aboveand50%below)Mean=72.67Median=72Isthisenoughinformation?Copyright©2009CengageLearning1.7Example2.6StatsAnxietyAremostofthemarksclusteredaroundthemeanoraretheymorespreadout?Range=Maximum–minimum=92-53=39VarianceStandarddeviationCopyright©2009CengageLearning1.8Example2.6StatsAnxietyAretheremanymarksbelow60orabove80?WhatproportionareA,B,C,Dgrades?Agraphicaltechnique–histogramcanprovideuswiththisandotherinformationCopyright©2009CengageLearning1.9Example2.6StatsAnxietyHistogram01020305060708090100MarksFrequencyCopyright©2009CengageLearning1.10DescriptiveStatisticsDescriptivestatisticsdealswithmethodsoforganizing,summarizing,andpresentingdatainaconvenientandinformativeway.Oneformofdescriptivestatisticsusesgraphicaltechniques,whichallowstatisticspractitionerstopresentdatainwaysthatmakeiteasyforthereadertoextractusefulinformation.Chapter2introducesseveralgraphicalmethods.Copyright©2009CengageLearning1.11DescriptiveStatisticsAnotherformofdescriptivestatisticsusesnumericaltechniquestosummarizedata.Themeanandmedianarepopularnumericaltechniquestodescribethelocationofthedata.Therange,variance,andstandarddeviationmeasurethevariabilityofthedataChapter4introducesseveralnumericalstatisticalmeasuresthatdescribedifferentfeaturesofthedata.Copyright©2009CengageLearning1.12Case12.1Pepsi’sExclusivityAgreementAlargeuniversitywithatotalenrollmentofabout50,000studentshasofferedPepsi-ColaanexclusivityagreementthatwouldgivePepsiexclusiverightstosellitsproductsatalluniversityfacilitiesforthenextyearwithanoptionforfutureyears.Inreturn,theuniversitywouldreceive35%oftheon-campusrevenuesandanadditionallumpsumof$200,000peryear.Pepsihasbeengiven2weekstorespond.Copyright©2009CengageLearning1.13Case12.1Pepsi’sExclusivityAgreementThemarketforsoftdrinksismeasuredintermsof12-ouncecans.Pepsicurrentlysellsanaverageof22,000cansperweek(overthe40weeksoftheyearthattheuniversityoperates).Thecanssellforanaverageof75centseach.Thecostsincludinglaboramountto20centspercan.Pepsiisunsureofitsmarketsharebutsuspectsitisconsiderablylessthan50%.Copyright©2009CengageLearning1.14Case12.1Pepsi’sExclusivityAgreementAquickanalysisrevealsthatifitscurrentmarketsharewere25%,then,withanexclusivityagreement,Pepsiwouldsell88,000(22,000is25%of88,000)cansperweekor3,520,000cansperyear.Theprofitorlosscanbecalculated.Theonlyproblemisthatwedonotknowhowmanysoftdrinksaresoldweeklyattheuniversity.Copyright©2009CengageLearning1.15Case12.1Pepsi’sExclusivityAgreementPepsiassignedarecentuniversitygraduatetosurveytheuniversity'sstudentstosupplythemissinginformation.Accordingly,sheorganizesasurveythatasks500studentstokeeptrackofthenumberofsoftdrinkstheypurchaseinthenext7days.Theresponsesarestoredinafileonthediskthataccompaniesthisbook.Case12.1Copyright©2009CengageLearning1.16InferentialstatisticsTheinformationwewouldliketoacquireinCase12.1isanestimateofannualprofitsfromtheexclusivityagreement.Thedataarethenumbersofcansofsoftdrinksconsumedin7daysbythe500studentsinthesample.Wewanttoknowthemeannumberofsoftdrinksconsumedbyall50,000studentsoncampus.Toaccomplishthisgoalweneedanotherbranchofstatistics-inferentialstatistics.Copyright©2009CengageLearning1.17InferentialstatisticsInferentialstatisticsisabodyofmethodsusedtodrawconclusionsorinferencesaboutcharacteristicsofpopulationsbasedonsampledata.Thepopulationinquestioninthiscaseisthesoftdrinkconsumptionoftheuniversity's50,000students.Thecostofinterviewingeachstudentwouldbeprohibitiveandextremelytimeconsuming.Statisticaltechniquesmakesuchendeavorsunnecessary.Instead,wecansampleamuchsmallernumberofstudents(thesamplesizeis500)andinferfromthedatathenumberofsoftdrinksconsumedbyall50,000students.WecanthenestimateannualprofitsforPepsi.Copyright©2009CengageLearning1.18Example12.5Whenanelectionforpoliticalofficetakesplace,thetelevisionnetworkscancelregularprogrammingandinsteadprovideelectioncoverage.Whentheballotsarecountedtheresultsarereported.However,forimportantofficessuchaspresidentorsenatorinla