Zekeriya Aktürk, Prof. Atatürk University Medical Faculty , Class 1 25.10.2010, Erzurum

1. Biostatistics Introduction Zekeriya Aktürk, Prof. Atatürk UniversityMedicalFaculty, Class 1 25.10.2010, Erzurum http://aile.atauni.edu.tr zekeriya.akturk@gmail.com / 27

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3. Aims – Objectives • At the end of this lecture, the participants should defend the importance of research and have basic information about research and biostatistics. • Name the steps of research • Formulate an answerable clinical question • Classify types of data • Mention features of a data • Classify different types of studies • Explain cohort, case control, and randomized controlled studies / 27

4. Lets do a study together AU Medical Faculty Students and Research / 27 Aktürk Z. Erzurum. October 25, 2009

5. Bir literatür Askew, DA. et al.GPs involvement in and attitudes to research.Med J Aust2002;177(2):74-77 / 27

6. Stages of a study • Ask a question • Is the question already answered? • Formulate hypothesis • Design the method • Apply • Perform analysis • Discussion • Report Tyler CW, Epidemyology / 27

7. Most important: idea / 27

8. How to gather ideas? • Clinical practice • Work environment • Ideas from patients • Colleagues • Unexpected health outcomes • … / 27

9. Answerable clinical question • Patient/problem Hasta/problem • Intervention Girişim • Comparison Karşılaştırma • Outcomes Sonuç/Çıktı Is there any difference among a calorie diet and a glycemic diet in decreasing body mass index of obese women? / 27 Centre for EBM http:www.cebm.net/

10. Is your question answered? • Literature search • Teachers • Colleagues • Books • Internet • … / 27

11. Formulating a hypothesis • H0 • There is no difference between a calorie diet and a glycemic diet in decreasing body mass index of obese women? • H1 • There is a difference between a calorie diet and a glycemic diet in decreasing body mass index of obese women? / 27

12. Types of studies(How to answer the question?) • Observation • Case report • Prevalance • Case control • Cohost studies • Qualitative studies • Intervention • Randomized controlled studies • Methodologic • Validity • Reliability / 27

13. Cases Controls TIME Not exposed Exposed Not exposed Exposed Case control study / 27

14. Population Not exposed Exposed T I M E Diseases Diseased Healthy Healthy Cohort study / 27

15. Population Randomization B therapy A therapy Sick Sick Improved Improved T I M E Randomized controlled study / 27

16. Statistical analysis • Features of data • Current • Reliable • Correct • Complete • Appropriate to use • Appropriate for aim / 27

17. Statistical analysis • Frequency distribution • Importance tests (hypothesis tests) • Student t-test • ANOVA • Chi square • Mann-Whitney U test • McNemar test • Wilcoxon • Fisher exact test • … / 27

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19. Lets do an example • Stages of a study • Ask a question • Is the question already answered? • Formulate hypothesis • Design the method • Apply • Perform analysis • Discussion • Report / 27

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21. Ask a question • Is there any difference in recognizing “thyme” between class 1 and class 6 medical students? / 27

22. Was the question answered? • Aktürk Z ve ark. • Medical students have problems in recognizing herbs. Class six students are better in recognizing. Genel Tıp Derg 2003;16(3):101-106 / 27

23. Hypothesis • H0: There is no difference in recognizing “thyme” between class 1 and class 6 medical students? • H1: There is a difference in recognizing “thyme” between class 1 and class 6 medical students? / 27

24. Method • The following picture was shown to students from class 1 and 6 by a data projector / 27

25. Statistics – Frequency distribution / 27

26. Statistics – hypothesis testing / 27

27. Conclusion • While 12% of class 1 students correctly recognized thyme, this was 78% in class 6. • Although class 6 students are better in recognizing thyme, still 22% are not successfull in recognizing. • There is a significant difference between class 1 and 6 students in recognizing thyme (p<0,001). / 27