1. DATA BASICS By Farrokh Alemi, Ph.D.

2. How best to collect data? Statistics Is

3. How should it be analyzed? Statistics Is

4. What can we infer from the analysis? Statistics Is

5. Does Stent Reduce Risk of Stroke? Case Study

6. Is Stent Effective?

8. Summary Statistic Is Stent Effective?

9. Are differences large enough? Is Stent Effective?

10. StrokeNo EventTotal Stent45179224 No stent28199227 Total73378451

11. Is Stent Effective? StrokeNo EventTotalRate Stent45179224=45/224 No stent28199227=28/227 Total73378451

12. Is Stent Effective? StrokeNo EventTotalRate Stent4517922420% No stent2819922712% Total73378451 Summary Statistics

13. Is Stent Effective? StrokeNo EventTotalRate Stent4517922420% No stent2819922712% Total73378451 Is the 8% difference real?

14. Is Stent Effective? StrokeNo EventTotalRate Stent4517922420% No stent2819922712% Total73378451 Real difference or chance event ?

15. If cases and matched controls (or treatment and controls) have real differences Take Home Message