CHAPTER 9
3) Mr.ȱMarshȱwantsȱtoȱseeȱifȱsmokersȱlikeȱtoȱgambleȱatȱcasinos.ȱOnceȱheȱhasȱhisȱdata,ȱheȱplotsȱthe informationȱinȱaȱscattergram.ȱWhatȱthreeȱaspectsȱofȱtheȱbivariateȱrelationshipȱwillȱthe scattergramȱreveal?ȱExplainȱtheȱsignificanceȱofȱeach. Answer: Formȱ-ȱrelationshipsȱbetweenȱtwoȱvariablesȱcanȱbeȱindependent,ȱlinear,ȱorȱcurvilinear. Independenceȱorȱnoȱrelationshipȱlooksȱlikeȱaȱrandomȱscatterȱwithȱnoȱpatter Directionȱ-ȱpositiveȱrelationshipȱmeansȱhigherȱvaluesȱgoȱwithȱhigherȱvalues.ȱnegative relationshipȱmeansȱhigherȱvaluesȱonȱoneȱvariableȱgoȱwithȱlowerȱvaluesȱonȱtheȱother. Precisionȱ-ȱmeasuresȱassociationȱ-ȱhighȱprecisionȱoccursȱrightȱonȱtheȱline.ȱAmountȱof spreadȱamongȱtheȱpointsȱindicatesȱprecision. Diff:ȱ2 PageȱRef:ȱ246 Skill: Application
4) Whatȱisȱtheȱpurposeȱofȱmultipleȱregressionȱanalysis?ȱWhatȱtwoȱthingsȱdoesȱitȱtellȱaȱresearcher? Answer: Multipleȱregressionȱforȱanalysisȱofȱnonexperimentalȱdataȱanalysis.ȱItȱisȱonlyȱforȱinterval andȱratio-levelȱdata.ȱPowerȱofȱmultipleȱregressionȱisȱanȱabilityȱtoȱcontrolȱforȱmany variablesȱsimultaneously.ȱR-squaredȱisȱtheȱpercentageȱofȱpredictionȱaccuracy,ȱ20 percentȱisȱveryȱgoodȱinȱsocialȱscience,ȱmeaningȱthatȱindependentȱvariablesȱexplainȱ20 percentȱofȱchangeȱinȱtheȱdependentȱvariable.ȱPercentȱisȱbasedȱonȱimprovementȱover zero.ȱBetaȱcoefficientȱtellsȱsizeȱandȱdirectionȱofȱeffectsȱonȱeachȱindependentȱvariableȇs impactȱonȱaȱdependentȱvariable. Diff:ȱ2 PageȱRef:ȱ254 Skill: Knowledge
5) Whatȱdoesȱanȱ.01ȱlevelȱofȱsignificanceȱmean? Answer: Itȱmeansȱthatȱresultsȱareȱdueȱtoȱchanceȱfactors.ȱOnlyȱ1ȱinȱ100ȱmeansȱthereȱisȱaȱ99ȱpercent chanceȱthatȱtheȱsampleȱresultsȱareȱnotȱdueȱtoȱchanceȱfactorsȱalone,ȱbutȱreflectȱthe populationȱaccurately.ȱItȱmeansȱtheȱoddsȱofȱsuchȱresultsȱbasedȱonȱchanceȱaloneȱareȱ.01 orȱ1ȱpercent.ȱItȱmeansȱoneȱcanȱbeȱ99ȱpercentȱconfidentȱthatȱtheȱresultsȱareȱdueȱtoȱaȱreal relationshipȱinȱtheȱpopulations,ȱnotȱchanceȱfactors. Diff:ȱ2 PageȱRef:ȱ256 Skill: Application
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