25/1/26HarbinUniversityofCommerce1StatisticsWhatisStatistics?Statisticsisaboutgathering,communicating,analyzingandinterpretingdata.Statisticsisawaytogetinformationfromdata.Statisticsisatoolforcreatingnewunderstandingfromasetofnumbers.http://www.lijundata.com/eStatistics/25/1/26HarbinUniversityofCommerce21.DataInthischapterwebeginthestoryby:IntroducingvarioustypesofdataPresentingdataintheformbarcharts,piecharts,frequencylinediagrams,stem-and-leafdisplays,histograms,frequencydensitypolygonsandcurves.InformationandDataStatisticsisallaboutgathering,communicating,analyzingandinterpretinginformation.Theinformationisobtainedfromvarioussources,andinitsbasicformitiscalleddata.Theretwodistincttypesofdata,whicharequalitativeandquantitative.PayPlay25/1/26HarbinUniversityofCommerce3QualitativedataQualitativeinformation,asthetermsuggests,isdescriptiveinformation.Itmaybeexpressedasaproperty,orintermsofcategories,orasaqualityforexample:color,gender,nationality,style,…Wherethecategoriesarewelldefinedanddistinct,theinformationmaybedescribedasdiscrete.Forinstance,themakeofacalculatorfallsintoexactlyoneofthefollowingcategories:Canon,Casio,Sharp,Texas,HewlettPackard,other.ThereisnoinherentreasonwhyCasioshouldalwaysprecede–orindeedshouldneverfollow–Texas.Thereisnonaturalhierarchy,noinbuiltorderwithinthesecategories.Play25/1/26HarbinUniversityofCommerce4QuantitativedataIInformationthathasanaturalhierarchy,suchasdatainnumericalmaybedescribedasquantitative.Suchnumericalinformationmaybeseparatedintocontinuousdataanddiscretedata.Whenmeasurementsaremade,thedatagatheredaregenerallycontinuoussinceallvalueswithinaparticularspanarepossible.Anexampleofthisisthelengthofaperson’sstride,whichmightbeanylengthbetween,say,0.3mand1.3m.Play25/1/26HarbinUniversityofCommerce5QuantitativedataIIDiscretedataareusuallyobtainedbycounting.Forexample,thenumberoflettersdelivereddailytoahousemightbe0,1,2,3,4,5,…oranyotherintegerbutitcannotbeanyothersortofnumber.Discretedatamayalsoarisewhenthereisanorderin...
