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2/21/2015
1
Business Research Method
Prof. Ravi Shekhar KumarSession-9
Liveeachdayasifyourlifehadjustbegun.JohannWolfgangVonGoethe
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Recapoflastsession ElementaryDataAnalysis
FrequencyDistribution IntroductiontoHypothesisTesting CrossTabulation ParametricTests
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Agendaforthissessions ElementaryDataAnalysis
ParametricTests NonparametricTests
Introductiontoobservationalstudies
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ElementaryHypothesisTesting
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Independent Samples
Paired Samples Independent
SamplesPaired Samples
* Two-Group t test
* Z test * Paired
t test * Chi-Square* Mann-Whitney* Wilcoxon
Hypothesis Tests
One Sample Two or More Samples
One Sample Two or More Samples
* t test* Z test
* K-S * Chi-Square * Runs* Binomial
Parametric Tests (Metric Tests)
Non-parametric Tests (Nonmetric Tests)
ParametricTest OneSampleTest TwoindependentSampletest PairedSampletest
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InternetUsageData
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Respondent Sex Familiarity Internet Attitude Toward Usage of InternetNumber Usage Internet Technology Shopping Banking1 1.00 7.00 14.00 7.00 6.00 1.00 1.002 2.00 2.00 2.00 3.00 3.00 2.00 2.003 2.00 3.00 3.00 4.00 3.00 1.00 2.004 2.00 3.00 3.00 7.00 5.00 1.00 2.00 5 1.00 7.00 13.00 7.00 7.00 1.00 1.006 2.00 4.00 6.00 5.00 4.00 1.00 2.007 2.00 2.00 2.00 4.00 5.00 2.00 2.008 2.00 3.00 6.00 5.00 4.00 2.00 2.009 2.00 3.00 6.00 6.00 4.00 1.00 2.0010 1.00 15.00 7.00 6.00 1.00 2.0011 2.00 4.00 3.00 4.00 3.00 2.00 2.0012 2.00 5.00 4.00 6.00 4.00 2.00 2.0013 1.00 6.00 9.00 6.00 5.00 2.00 1.0014 1.00 6.00 8.00 3.00 2.00 2.00 2.0015 1.00 6.00 5.00 5.00 4.00 1.00 2.0016 2.00 4.00 3.00 4.00 3.00 2.00 2.0017 1.00 6.00 9.00 5.00 3.00 1.00 1.0018 1.00 4.00 4.00 5.00 4.00 1.00 2.0019 1.00 7.00 14.00 6.00 6.00 1.00 1.0020 2.00 6.00 6.00 6.00 4.00 2.00 2.0021 1.00 6.00 9.00 4.00 2.00 2.00 2.0022 1.00 5.00 5.00 5.00 4.00 2.00 1.0023 2.00 3.00 2.00 4.00 2.00 2.00 2.0024 1.00 7.00 15.00 6.00 6.00 1.00 1.0025 2.00 6.00 6.00 5.00 3.00 1.00 2.0026 1.00 6.00 13.00 6.00 6.00 1.00 1.0027 2.00 5.00 4.00 5.00 5.00 1.00 1.0028 2.00 4.00 2.00 3.00 2.00 2.00 2.00 29 1.00 4.00 4.00 5.00 3.00 1.00 2.0030 1.00 3.00 3.00 7.00 5.00 1.00 2.00
TwoIndependentSampleTest ComparingMeanoftwosample IfwewanttotestWhetherthemeanoffamiliaritywithinternetformale&femaleisdifferentorsame,Wellusetwoindependentsamplettest.
Resultwillshowwhetherfamiliaritywithinternetissameordifferentformale&female.
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TwoIndependentSampleTest Inthecaseofmeansfortwoindependentsamples,thehypothesestakethefollowingform.
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210 : H 211 : H
TwoIndependentSampleTest AnFtestofsamplevariancemaybeperformedifitisnotknownwhetherthetwopopulationshaveequalvariance.Inthiscase,thehypothesesare:
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H0:12 =22H1:12 22
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TwoIndependentSampleTest
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Table 15.14
Summary Statistics
Number Standard of Cases Mean Deviation Male 15 9.333 1.137 Female 15 3.867 0.435
F Test for Equality of Variances F 2-tail value probability 15.507 0.000
t Test
Equal Variances Assumed Equal Variances Not Assumed t Degrees of 2-tail t Degrees of 2-tail value freedom probability value freedom probability 4.492 28 0.000 -4.492 18.014 0.000 -
PairedSampleTest ComparingMeansofPairedSample Ifwewanttotestthewhethermeanofattitudetowardsinternet&attitudetowardstechnologyissameornot,Wellusepairedsamplettest.
Resultwillshowwhetherattitudetowardsinternet&attitudetowardstechnologyissameordifferentforthesample.
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PairedSampleTest Thedifferenceinthesecasesisexaminedbyapairedsamplesttest.Tocomputetforpairedsamples,thepaireddifferencevariable,denotedbyD,isformedanditsmeanandvariancecalculated.Thenthetstatisticiscomputed.Thedegreesoffreedomaren 1,wherenisthenumberofpairs.
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H0: D = 0H1: D 0
PairedSampleTest
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Number Standard StandardVariable of Cases Mean Deviation Error
Internet Attitude 30 5.167 1.234 0.225Technology Attitude 30 4.100 1.398 0.255
Difference = Internet - Technology
Difference Standard Standard 2-tail t Degrees of 2-tailMean deviation error Correlation prob. value freedom probability
1.067 0.828 0.1511 0.809 0.000 7.059 29 0.000
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TwoIndependentSamplesProportions ThenumberofmalesandfemaleswhousetheInternetforshopping.IstheproportionofrespondentsusingtheInternetforshoppingthesameformalesandfemales?
Thenullandalternativehypothesesare:
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H0: 1 = 2H1: 1 2
NonParametricTest
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ElementaryHypothesisTesting
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Independent Samples
Paired Samples Independent
SamplesPaired Samples
* Two-Group t test
* Z test * Paired
t test * Chi-Square* Mann-Whitney* Wilcoxon
Hypothesis Tests
One Sample Two or More Samples
One Sample Two or More Samples
* t test* Z test
* K-S * Chi-Square * Runs* Binomial
Parametric Tests (Metric Tests)
Non-parametric Tests (Nonmetric Tests)
NonparametricTests Nonparametrictests areusedwhentheindependentvariablesarenonmetric.
Likeparametrictests,nonparametrictestsareavailablefortestingvariablesfromonesample,twoindependentsamples,ortworelatedsamples.
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NonparametricTestsOneSample Sometimesresearcherwantstotestwhethertheobservationsforaparticularvariablecouldreasonablyhavecomefromaparticulardistribution.
KolmogorovSmirnov(KS)onesampletestisonesuchgoodnessoffittest.
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KSOneSampleTest
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Test Distribution - Normal
Mean: 6.600 Standard Deviation: 4.296
Cases: 30
Most Extreme Differences Absolute Positive Negative K-S z 2-Tailed p 0.222 0.222 -0.142 1.217 0.103
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OneSample:NonparametricTests Chisquaretest canbeperformedonasinglevariablefromone
sample.Inthiscontext,thechisquareservesasagoodnessoffittest.
Runstest isatestofrandomnessfordichotomousvariables.(Todeterminewhethertheorderorsequenceinwhichobservationsareobtainedisrandom)
Binomialtest isalsoagoodnessoffittestfordichotomousvariables.
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TwoIndependentSample:NonparametricTest Whenthedifferenceinthelocationoftwopopulationsistobe
comparedbasedonobservationsfromtwoindependentsamples,andthevariableismeasuredonanordinalscale,MannWhitneyUtestcanbeused.
InMannWhitneyUtest,twosamplesarecombinedandcasesarerankedinorderofincreasingsize.
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MannWhitneyU:InternetUsagebyGender
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Sex Mean Rank Cases
Male 20.93 15Female 10.07 15
Total 30
Corrected for tiesU W z 2-tailed p
31.000 151.000 -3.406 0.001
NoteU = Mann-Whitney test statisticW= Wilcoxon W Statisticz = U transformed into normally distributed z statistic
PairedSample:NonparametricTest Wilcoxonmatchedpairssignedrankstestanalyzesthedifferences
betweenthepairedobservations,takingintoaccountthemagnitudeofthedifferences.
Itcomputesthedifferencesbetweenthepairsofvariables&ranksabsolutedifferences.
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PairedSample:NonparametricTest
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(Technology - Internet) Cases Mean rank -Ranks 23 12.72 +Ranks 1 7.50 Ties 6 Total 30 z = -4.207 2-tailed p = 0.0000
ElementaryHypothesisTesting
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Independent Samples
Paired Samples Independent
SamplesPaired Samples
* Two-Group t test
* Z test * Paired
t test * Chi-Square* Mann-Whitney* Wilcoxon
Hypothesis Tests
One Sample Two or More Samples
One Sample Two or More Samples
* t test* Z test
* K-S * Chi-Square * Runs* Binomial
Parametric Tests (Metric Tests)
Non-parametric Tests (Nonmetric Tests)
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Non-experimental research
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WhytoConductObservationResearch Observationalstudiesarebestsuitedfor
Earlystagesofresearchorwhenyouareinterestedinstudyingnaturallyoccurringbehaviorofthesubjects
Whenconductingexperimentsmaynotbepossible
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EssenceofObservationalResearch Observationalstudiesarepurelyobservationalintwosenses
1. Theyarecorrelationaldesignsandthusdontinvolvemanipulatingindependentvariable
2. Allusetrainedresearcherstoobservesubjectsbehaviors
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CopingwithComplexity Difficultyinobservingbehavior
Naturaloccurringbehaviorisoftencomplexandfastpaced
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Approachtodatacollection Quantitativedata
Qualitativedata
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TechniqueQuantifyingBehaviorinObservationalStudy
FrequencyMethod Recordthenumberoftimesthataparticularbehavioroccurswithinatimeperiod.
DurationMethod Recordthedurationofeachverballyaggressiveactdisplayedbychild
IntervalMethod Dividetheobservationperiodintodiscretetimeintervalsandthenrecordwhetherabehavioroccurswithineachinterval
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NonexperimentalResearchDesign NaturalisticObservation&Ethnography
Observingsubjectsintheirnaturalenvironment Makingunobtrusiveobservation/immersedinthebehaviororsocialsystembeingstudied
InvolvesHabituatingthesubjects Highexternalvalidity But.Timeconsuming&Expensive
Example Observingchildreninadaycare
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NonexperimentalResearchDesign Sociometry
Identifyingandmeasuringinterpersonalrelationshipswithinagroup
Example Systematicstudyoffriendshippatterntoseeifthereisanyrelationshipbetweenfriendshipchoice&leadershiproles
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NonexperimentalResearchDesign CaseHistory
Adescriptivetechniqueinwhichyouobserveandreportacase
Example Canbeusedtodescribetypicaldevelopmentofadisease
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NonexperimentalResearchDesign ArchivalResearch
Involvesstudyingexistingrecords.Theserecordscanbehistoricalaccountsofevent,censusdata,courtrecords,publishedresearcharticles
Example Whydontmorewomenplaychess?
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NonexperimentalResearchDesign ContentAnalysis
Whenyouwanttoanalyzeawrittenorspokenrecord fortheoccurrenceofspecificcategoriesorevents(suchaspauseinaspeech),items(suchasnegativecomments),orbehavior(suchasfactualinformationofferedduringgroupdiscussion).
Unitofanalysisissomewritten,visualorspokenrecord ratherthanbehaviorofparticipant
Example Contentanalysisofchatroomonsocialnetworkingsites
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SamplingTechniqueforbehavioralobservation TimeSampling
Scanthegroupforaspecificperiodoftime&recordtheobservationalbehaviorforthenextperiod
IndividualSampling Selectasinglesubjectforobservationoveragiventimeperiod
EventSampling Observeonlyonebehavior&recordallinstancesofthatbehavior
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