Suppose an illness that can affect 1% of the people. Also assume that there is a test for that illness, that gives the correct result 99% of the times.

If you take that test, and receive a POSITIVE result, should you worry much?

If you take it again, and once more get a POSITIVE, should you worry then?

How many consecutive POSITIVEs would you have to get in order to be sure that the chances of a wrong diagnostic are 1 in a million?

The word positive could mean a good result or that the test came up positive. In both situations the answer would be dont worry and worry respectively.

I personally think the first answer is true so my answer is no, you shouldnt worry.

For the last question I would say 10 000 times, but thats really more mathematics than word problem!

Posted by Angela on 2005-01-03 17:28:48