4 ms·
That's a nitpick on a correct statement. Unless two tests are always perfectly correlated, you will reduce your uncertainty. They don't need to be independent.
by ucha 11y ago
That's a nitpick on a correct statement. Unless two tests are always perfectly correlated, you will reduce your uncertainty. They don't need to be independent.
- DINKDINK 11y agoExactly, unless the false positive is causal some how, testing again will reduce the uncertainty some amount. Though that amount may be less than if the false positive isn't completely independent.
- darawk 11y agoSorry, I should have provided a more complete quote: > If you get tested again, you can reduce your uncertainty enormously, because your probability of having cancer, P(B), is now 50 percent rather than one percent. If your second test also comes up positive, Bayes’ theorem tells you that your probability of having cancer is now 99 percent, or .99. This statement is incorrect if the results are correlated at all.