Cronbach's Alpha (Reliability of test scores) · PDF file · 2016-12-27UKCAT and...

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Transcript of Cronbach's Alpha (Reliability of test scores) · PDF file · 2016-12-27UKCAT and...

HowdoIreportthestatisticalproceduresusedintheAmericanPsychologicalAssociation(APA)guidelines?Mean=M;StandardDeviation=SDForexample:Themeanscoreontheempathyscalewas130(SD=10.12).PercentageForexample:Approximatelyhalf(51%)ofthesamplewerefemalestudents.CorrelationsForexample:TheresultsshowthatthereisastrongcorrelationbetweentheEbelratingsandstudentability(r=0.88,p=0.03).MultipleLinearRegressionForexample:AmultiplelinearregressionwasusedtopredictstudentperformancebasedonUKCATandinterviewscores.TheUKCATandinterviewscoresdidnotpredictstudentperformance(β=.12,t(445)=0.1.81,p=0.34).TheUKCATandtheinterviewscoresexplainanon-significantofthevarianceinstudentscores(R2=0.01,F(2,334)=0.99,p=0.56).T-TestsForexample:Thereisastatisticallysignificantdifferencebetweentheempathyscoresandgender(t(345)=3.2,p=0.01),withfemalestudentsreceivinghigherscoresthanmalestudents.Thereisnoasignificantdifferenceintheempathyscoresbetweenfemale(M=110,SD=11.3)andmale(M=110.5,SD=10.5)students(t(345)=1.66,p=0.11).AnalysisofVariance(ANOVA)Forexample:Thereisastatisticallysignificantdifferencebetweentheempathyscoresandyearsofmedicalschool(F(14,775)=4.98,p=0.04).ATukeypost-hoctestindicatesthatthereisastatisticallysignificantdifferencebetweentheemptyscoresandyear1(M=125,p=0.041)andyear2(M=120,p=0.00)comparedtoyear5(M=90).Thereisnoasignificantdifferenceintheempathyscoresforyear3andyear4ofmedicaleducation(p=0.21). Chi-SquareTestForexample:Thereisnoastatisticallysignificantassociationbetweengenderandthepass/faildecision(χ2(1,N=220)=0.44,p=0.21).Mann-WhitneyUTestForexample:AMann-WhitneyUtestshowsthatfemalestudents(Mdn=110)outperformmalestudents(Mdn=92)ontheempathyscale(U=44.3,p=0.01).Kruskal-WallisHTestForexample:AKruskal-WallisHtestwasperformedtoexploretheempathyscoresasstudentsprogressthroughmedicaleducation,i.e.year1toyear5.Thereisastatisticallysignificantdifferencebetweentheempathyscoresandyearsofmedicalschooltraining(χ2(2,

N=24)=4.21,p=0.02)withameanrankempathyscoreof20foryear1,14foryear2,12foryear3,10foryear4and9foryear5.TheresultsoftheBonferroniposthoctestshowasignificantdifferencebetweentheempathyscoreandyear5ofmedicalschool.Cronbach'sAlpha(Reliabilityoftestscores)TheJeffersonScaleofEmpathyconsistedof20itemswiththreesubscales.ThePerspectiveTakingsubscaleconsistedof10items(Alpha=0.74),theCompassionateCaresubscaleconsistedof8items(Alpha=0.70),andtheWakinginthePatient’sShoessubscaleconsistedof2items(Alpha=0.58).FactoranalysisForexample,sayyouhavedevelopedascalewith22itemstomeasureaspecificconstruct.Theseitemshavebeensubjectedtoexploratoryfactoranalysis(EFA),assumingthefactoranalysisapproachissuitablewithall22items.Consideringthreefactors/componentshavebeenemergedfromtheEFAmethod,thefollowingtablesneedtobereported:Table1.PrinciplecomponentanalysisoftheXscalewithcommunalitiesofeachitem(N=xx)

Item Factor1 Factor2 Factor3 h2 Mean SD1 0.65 0.85 4.8 1.22 0.63 0.80 4.3 1.13 0.62 0.78 4.6 1.04 0.60 0.76 4.9 0.55 0.59 0.73 4.7 0.26 0.58 0.72 4.6 0.37 0.54 0.70 4.2 0.78 0.50 0.69 4.1 0.69 0.48 0.60 4.0 0.410 0.44 0.64 4.8 0.411 0.60 0.71 4.9 0.912 0.56 0.70 4.7 1.313 0.52 0.69 4.1 1.514 0.51 0.58 4.0 1.115 0.44 0.52 3.9 1.916 0.40 0.51 3.0 1.017 0.33 0.52 4.1 0.918 0.51 0.45 4.9 1.719 0.50 0.44 4.0 1.420 0.44 0.42 4.8 1.321 0.32 0.40 4.7 1.222 0.30 0.64 3.9 1.2

%Variance 44.1 17.1 11.2 Note:Factorloadinglessthan0.30wereremoved

Table2.DescriptivestatisticsforthethreeXfactors(N=xx)

No.Items Cronbach’salpha M(SD) Skewness KurtosisFactor1 10 0.80 4.1(1.1) 0.45 0.39Factor2 7 0.75 4.0(0.8) 0.44 0.44Factor3 5 0.69 4.5(1.2) 0.61 0.11

Note:Factorsshouldbenamed/labelled.Forexample,theitemsthathavebeenloadedinFactor1cabbenamed/labelledasxxx.Note:Allvaluesprovidedaredummy.