Session 9 21

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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


* 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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Independent Samples



* Two-Group t test

* Z test * Paired


Hypothesis Tests



* t test* Z test




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


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Independent Samples



* Two-Group t test

* Z test * Paired


Hypothesis Tests



* t test* Z test




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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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Documents

Session 9 21