Ray's Wife Proves He's All Wet

RAY: The real question is if the test comes back positive what is the real probability that you actually have the bucolic plague?

Let's say that where you live there are a million people, and .1 percent, or a thousand people out of a million, have the disease.

If the 999,000 disease-free people are tested, the results will say that one percent of them, or 9,990 have the disease when, in fact, they don't.

TOM: They're misdiagnosed!

RAY: Correct. And of the thousand people who do have the disease, the test results will say that 99% of them, or 990 have the disease. So we have a total of 10,980 positive results.

But, we know that out of a million people, only a thousand people really do have the disease. So, the chance that you have Bucolic Plague if you test positive is about one in eleven, or less than 10%.

The moral of the story is this: You shouldn't lock yourself in the bathroom, unless you have some really good magazines. Do we have a winner?

TOM: Of course! The winner is Jean Gaska from Shelbyana, Kentucky. For having her answer selected at random from all the correct answers that we got, Jean gets a $26 dollar gift certificate to the Shameless Commerce Division of Cartalk.com, where she can choose from a wide array of fine quality Car Talk junk.

[ Car Talk Puzzler ]