Statistics & research Statistics & research methods for cliniciansmethods for clinicians

Ramez Reda MoustafaRamez Reda Moustafa

ObjectivesObjectives

Introduce statistical and research methods Introduce statistical and research methods commonly used in the medical sciencescommonly used in the medical sciencesBreak the psychological barrierBreak the psychological barrierIntroduce the basics of scientific writing Introduce the basics of scientific writing and publishing in medicineand publishing in medicine

What this course is notWhat this course is not

A comprehensive course on statisticsA comprehensive course on statisticsA series of lecturesA series of lectures

What I am notWhat I am not

A statisticianA statistician

TYPES OF DATATYPES OF DATA

Categorical - NominalCategorical - Nominal Yes/NoYes/No Male/FemaleMale/Female Red/White/BlackRed/White/Black

OrdinalOrdinal mild/moderate/severemild/moderate/severe Low/normal/highLow/normal/high

TYPES OF DATATYPES OF DATA

Continuous (quantitative, numerical)Continuous (quantitative, numerical) AgeAge Blood pressureBlood pressure ESRESR

What type?What type?

Glasgow coma scaleGlasgow coma scaleModified Rankin scaleModified Rankin scaleHbHbSplenomegalySplenomegalyFeverFeverDysphasiaDysphasia

SamplesSamples

Related or independent, that is the Related or independent, that is the question. question.

     

CategoricalCategorical Ordinal or Non-Normal Ordinal or Non-Normal ContinuousContinuous Normal ContinuousNormal Continuous

     

One sampleOne sample Chi-squared testChi-squared test Kolmogorov-Smirnov testKolmogorov-Smirnov test one sample t-testone sample t-test

Two samplesTwo samples independentindependent Chi-squared or Fisher's exact Chi-squared or Fisher's exact testtest Mann-Whitney U testMann-Whitney U test Student t-testStudent t-test

pairedpaired McNemar's testMcNemar's test Wlcoxon Signed Rank testWlcoxon Signed Rank test Paired t-testPaired t-test

Multiple samples Multiple samples (k>2)(k>2) independentindependent Chi-squared testChi-squared test Kruskal-Wallis testKruskal-Wallis test ANOVAANOVA

relatedrelated Cochran-Q testCochran-Q test Friedman testFriedman test repeated measures ANOVArepeated measures ANOVA

VarianceVariance

N=1 studiesN=1 studies100% studies100% studies

CICISDSDSEMSEM

Sample sizeSample size

The “N”The “N”Pilot studiesPilot studies

Summarizing dataSummarizing data

The MeanThe MeanThe MedianThe MedianFrequency/proportionFrequency/proportion

Answering questionsAnswering questions

1.1. Asking the questionAsking the question2.2. What is my dataWhat is my data3.3. The methodThe method4.4. Hypothesis testing or notHypothesis testing or not

Collecting dataCollecting data

Lab bookLab bookformsformsSource dataSource dataComputerComputer ExcelExcel SPSSSPSS

The table(s)The table(s)Master sheet? What master sheet?Master sheet? What master sheet?

Collecting dataCollecting data

Too many variablesToo many variablesToo few variablesToo few variables

Looking through your dataLooking through your data

TablesTablesGraphsGraphsDescriptive statsDescriptive stats