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1、BasicStatistics UseofMinitab BeltonGroupRexWong 2 Statistics Statisticsisthebranchofsciencethatdealswiththecollection presentation analysis interpretationofdataforthepurposeofdecision makingandproblem solving Statisticsisacriticalskillinqualityimprovementasstatisticaltechniquescanbeusedtodescribeand
2、tounderstandvariability 3 Variability Variabilityistheresultofchangesintheconditionsunderwhichobservationsaremade Variabilitycancomeaboutduetochangesinmaterialqualitymachinesettingsorconditionsmanpowerstandardsmethodsofprocessingmeasurementmilieu environment 4 Population Sample Populationtheentirese
3、tofmeasurementsofinterestSampleasubsetofdatafromthepopulationParametersnumericalmeasuresofapopulationStatisticsnumericalmeasuresofasample 5 ParametervsStatistic ParameterStatisticMeanVarianceStandardDeviation 6 Typeofdata Gappiness Whethertherearegapsbetweensuccessivelyobservedvaluesofavariable Disc
4、reteVariablegapsexistbetweenobservationsobtainedbycountingContinuousVariablenogapsexistbetweenobservationsobtainedbymeasuring 7 Statistics Objectives Statisticsisthebranchofsciencethatdealswiththecollection presentation analysis interpretationofdataforthepurposeofdecision makingandproblem solving Ob
5、jectivesofStatistics datareduction DescriptiveStatisticsinferentialmeasurement InferentialStatisticsidentificationofrelationships Regression ANOVA 8 Statistics Overview 9 Descriptive InferentialStatistics DescriptiveStatisticscomprisesthosemethodsconcernedwithcollectinganddescribingasetofdatasoastoy
6、ieldmeaninginformationInferentialStatisticscomprisesthosemethodsconcernedwiththeanalysisofasubsetofdataleadingtopredictionsorinferencesabouttheentiresetofdata 10 DescriptiveStatistics Overview 11 NumericalMeasures Describesthecharacteristicsofthedataset Keynumericalmeasures measuresoflocation centra
7、ltendency measuresofdispersion variation measuresofshape distribution 12 MeasureofLocation Mean willnotbediscussed Median willnotbediscussed Mode willnotbediscussed Quartiles 13 Quartiles Whenanorderedsetofdataisdividedintofourequalparts thedivisionpointsarecalledquartiles ThefirstorlowerquartileQ1i
8、savaluethathasapproximately25 oftheobservationsbelowinvalue ThesecondquartileQ2isavaluethathasapproximately50 oftheobservationsbelowinvalue Itisalsocalledthemedian ThethirdorupperquartileQ3isavaluethathasapproximately75 oftheobservationsbelowinvalue 14 Quartiles Twentyorderedobservationsonthetimesto
9、failure inhours ofelectricalinsulationmaterialareshownbelow 2042282523003244446247208169121176129613921488151225202856319235283710 15 MeasureofDispersion Range Willnotbediscussed Variance Willnotbediscussed StandardDeviation Willnotbediscussed Inter QuartileRange 16 Inter quartilerange Theinter quar
10、tilerangeisanothermeasureofdispersion IQR Q3 Q1Theinter quartilerangeislesssensitivetoextremevaluesinasamplethantherange Forthetwosamples 1 3 5 8 9and1 5 5 5 9 theirinter quartilerangesare5and0respectively 17 MeasureofShape Skewness SkewnessThedegreeofassymmetryofadistributionarounditsmeanisreferred
11、toasitsskewness 18 MeasureofShape Kurtosis KurtosisKurtosischaracterizestherelativepeakednessorflatnessofadistributioncomparedtoanormal mesokurtic distribution 19 MiniTab sDescriptiveStatistics Stat BasicStatistics DisplayDescriptiveStatisticsproducesstatisticsforeachcolumnofdata orsubsetswithinacol
12、umn anddisplaysthemintheSessionWindowandoptionallyinagraphtheuserhasnocontroloverwhichstatisticsarecomputed displayedStat BasicStatistics StoreDescriptiveStatisticsdescriptivestatisticsforeachcolumn orsubsetswithinacolumn aredisplayedinadjacentcolumnswithintheWorksheettheusercanselectwhichstatistics
13、aretobecomputed displayed buthasnocontrolovertheorderinwhichtheyaredisplayedInstructorwillshowyouthemethodofusingMinitab 20 GraphicalPresentation Visualinterpretationthethedataset Commongraphicaltoolstoillustrateadataset DotPlotBoxPlotHistogramStem LeafDiagram 21 DotPlot Thedotplotisusefulfordisplay
14、ingasmallbodyofdata Thelocationorcentraltendencyinthedatasetanditsspreadordispersionareeasilyidentified Itcanalsobeusedincomparingtwoormoredatasets 22 DotPlot ThepullstrengthofbondingwiresfromtwosuppliersareshownbelowA 16 8516 4017 2116 3516 5217 0416 9617 1516 5916 57B 17 5017 6318 2518 0017 8617 7
15、518 2217 9017 9618 15TheDotPlotrevealsthatwiresfromsupplierAseemstoresultinlowerpullstrength butthevariabilitywithinbothgroupsisaboutthesame 23 Box WhiskersPlot BoxPlot The box displaysthelowerquartile Q1 themedian Q2 theupperquartile Q3 The whiskers extendtotheminimumthemaximumNottobeusedwhensample
16、sizeislessthan10units Median Maximum Minimum Q 1 Q 3 24 ProcedureformakingBoxPlot 1 Arrangethedatasetinascendingorder 2 Determinetheminimumandmaximum thelowerandupperquartiles themedian andTukey soutliers 3 Drawaboxthatextendsfromthelowerquartiletotheupperquartile themedianisalinedrawnthroughthebox 4 Drawlines orwhiskers thatextendfromtheendsoftheboxa fromQ1toMax Minimum Q1 1 5IQR b fromQ3toMin Maximum Q3 1 5IQR 5 Outliersarerepresentedbyappropriatesymbols 25 Histogram Thehistogram agraphicalpre
