Sensitivity and Specificity

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Click on the arrows to page through the tutorial on the statistical concepts of specificity and sensitivity. In my experience, people get confused when they try … Read the rest

Type One and Type Two Error

The purpose of inferential statistics is to predict differences between groups in the general population by measuring the difference in a small sample.


  • Blood pressure lowering of two drugs:
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Power Calculations

Statistical Power

OK, so John Lennon didn’t really write this , but statistical power is a very abstract concept and the ability to “imagine” really helps.

Power is the probability Read the rest

Number Needed to Treat

Definition:The Number Needed to treat is the number of patients that you would need to treat to prevent one primary outcome (heart attack, death, stroke, whatever)

  • This applies to
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Absolute vs Relative Risk Reduction

Albert and I developed an acute interest in risk reduction at about 3500 feet.


Example 1A:

  • Consider the benefit of using Coumadin for Stroke prevention in Atrial Fibrillation.
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Evils of Pickle Eating-101

Pickles are associated with all the major diseases of the body. Eating them breeds war and Communism. They can be related to most airline tragedies. Auto accidents are caused by … Read the rest