Business Statistics A DecisionMaking Approach, 6th edition1.ppt

businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-1,businessstatistics:adecision-makingapproach6thedition,chapter13introductiontolinearregressionandcorrelationanalysis,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-2,chaptergoals,aftercompletingthischapter,youshouldbeableto:calculateandinterpretthesimplecorrelationbetweentwovariablesdeterminewhetherthecorrelationissignificantcalculateandinterpretthesimplelinearregressionequationforasetofdataunderstandtheassumptionsbehindregressionanalysisdeterminewhetheraregressionmodelissignificant,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-3,chaptergoals,aftercompletingthischapter,youshouldbeableto:calculateandinterpretconfidenceintervalsfortheregressioncoefficientsrecognizeregressionanalysisapplicationsforpurposesofpredictionanddescriptionrecognizesomepotentialproblemsifregressionanalysisisusedincorrectlyrecognizenonlinearrelationshipsbetweentwovariables,(continued),businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-4,scatterplotsandcorrelation,ascatterplot(orscatterdiagram)isusedtoshowtherelationshipbetweentwovariablescorrelationanalysisisusedtomeasurestrengthoftheassociation(linearrelationship)betweentwovariablesonlyconcernedwithstrengthoftherelationshipnocausaleffectisimplied,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-5,scatterplotexamples,y,x,y,x,y,y,x,x,linearrelationships,curvilinearrelationships,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-6,scatterplotexamples,y,x,y,x,y,y,x,x,strongrelationships,weakrelationships,(continued),businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-7,scatterplotexamples,y,x,y,x,norelationship,(continued),businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-8,correlationcoefficient,thepopulationcorrelationcoefficient(rho)measuresthestrengthoftheassociationbetweenthevariablesthesamplecorrelationcoefficientrisanestimateofandisusedtomeasurethestrengthofthelinearrelationshipinthesampleobservations,(continued),businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-9,featuresofandr,unitfreerangebetween-1and1thecloserto-1,thestrongerthenegativelinearrelationshipthecloserto1,thestrongerthepositivelinearrelationshipthecloserto0,theweakerthelinearrelationship,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-10,r=+.3,r=+1,examplesofapproximatervalues,y,x,y,x,y,x,y,x,y,x,r=-1,r=-.6,r=0,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-11,calculatingthecorrelationcoefficient,where:r=samplecorrelationcoefficientn=samplesizex=valueoftheindependentvariabley=valueofthedependentvariable,samplecorrelationcoefficient:,orthealgebraicequivalent:,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-12,calculationexample,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-13,trunkdiameter,x,treeheight,y,calculationexample,(continued),r=0.886relativelystrongpositivelinearassociationbetweenxandy,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-14,exceloutput,excelcorrelationoutputtools/dataanalysis/correlation,correlationbetweentreeheightandtrunkdiameter,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-15,significancetestforcorrelation,hypothesesh0:=0(nocorrelation)ha:0(correlationexists)teststatistic(withn2degreesoffreedom),businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-16,example:producestores,isthereevidenceofalinearrelationshipbetweentreeheightandtrunkdiameteratthe.05levelofsignificance?,h0:=0(nocorrelation)h1:0(correlationexists)=.05,df=8-2=6,businessstatistics:adecision-makingapproach,6e2005prentice-hall,inc.,chap13-17,ex