Bayes Theorem: Difference between revisions

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==Calculations==
==Calculations==
{| class="wikitable" align="center"
|+ Two-by-two table for a diagnostic test
!colspan="2" rowspan="2"| || colspan="2"| Disease||
|-
| Present || Absent||
|-
| rowspan="3"|'''Test result''' || Positive || cell a|| cell b||Total with a positive test
|-
| Negative|| cell c|| cell d||Total with a negative test
|-
|  || Total with disease|| Total without disease||
|}
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Revision as of 06:40, 9 December 2007

Bayes Theorem is defined as "a theorem in probability theory named for Thomas Bayes (1702-1761). In epidemiology, it is used to obtain the probability of disease in a group of people with some characteristic on the basis of the overall rate of that disease and of the likelihoods of that characteristic in healthy and diseased individuals. The most familiar application is in clinical decision analysis where it is used for estimating the probability of a particular diagnosis given the appearance of some symptoms or test result".[1]

Calculations

Two-by-two table for a diagnostic test
Disease
Present Absent
Test result Positive cell a cell b Total with a positive test
Negative cell c cell d Total with a negative test
Total with disease Total without disease


References

  1. National Library of Medicine. Bayes Theorem. Retrieved on 2007-12-09.