Quote:
Originally Posted by ganzfeld
I don't understand your computations. Especially this part.

*sigh* Microsoft Excel works very well for this.
Using the above rates (true positive 99.7%, true negative 99.95%), an infection rate of 0.6%, and a population of 1 million, here's what I get.
1,000,000 total
994,000 healthy and 6,000 infected
5,982 true positives and 18 false negatives
993,503 true negatives and 497 false positives
So 5,982 true positives out of 6,479 total positives or 92.329% chance that a positive is true.
The ratio of 92.329% over 0.6% is 154  when the disease is very rare, this tends to an upper bound of the accuracy of the test, which in this case is 1:1990