RAY: There's a rare disease that's sweeping through your town. Of all the people who are exposed to it, 0.1 percent of the people actually contract the disease. There are no symptoms until the disease actually occurs. However, there's a diagnostic test that can detect the presence of the disease up to a year before it strikes.
You go to your doctor, and he administers the test. It comes out positive. You say, "I'm done for!"
Then you get a little bit encouraged. You say, "Wait a minute, doc, is this test 100 percent accurate?" Your doctor responds, "Well, not really. It's 95 percent accurate." In other words, 5 percent of the people who take the test will test positive but they don't really have the disease.
Here's the question: What are the chances that you actually have the disease?
RAY: Let's say 1000 people take the test. Fifty people will test positive and yet they will not have it. One will test positive and have it. So your chances of actually having it, even though you tested positive, are one in 51, or a little less than 2 percent. So who’s our winner?
(I disagree --- Ed)
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The Principle of Least Interest: He who cares least about a relationship, controls it.
