Tilted Forum Project Discussion Community - View Single Post - You've tested positive for cancer! How worried should you be?

yournamehere · 09-10-2003, 06:03 PM

Well, in that case, with a population of 10,000 - only 50 people would have <i>that</i> cancer, of which 49 would test positive.

Of the remaining 9,950 people who do not have cancer, there will be 9,751 who test negative, and 199 with false-positive results.

Therefore, of the 248 people who tested positive, only 49 of them really have cancer. So - roughly - only 1 in 5 positive results are actually correct. So there's an 80% chance you don't have cancer.

And, of course, there's one poor guy out there falsely believing he doesn't have cancer.
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Added later: Of course, this assumes <i>everyone</i> gets tested for cancer - in the real world, you wouldn't be tested for it unless you were showing some symptoms, or had abnormal test results.

09-10-2003, 06:03 PM	#4 (permalink)
yournamehere Invisible Location: tentative, at best	Well, in that case, with a population of 10,000 - only 50 people would have <i>that</i> cancer, of which 49 would test positive. Of the remaining 9,950 people who do not have cancer, there will be 9,751 who test negative, and 199 with false-positive results. Therefore, of the 248 people who tested positive, only 49 of them really have cancer. So - roughly - only 1 in 5 positive results are actually correct. So there's an 80% chance you don't have cancer. And, of course, there's one poor guy out there falsely believing he doesn't have cancer. ____________________________________________ Added later: Of course, this assumes <i>everyone</i> gets tested for cancer - in the real world, you wouldn't be tested for it unless you were showing some symptoms, or had abnormal test results. __________________ If you want to avoid 95% of internet spelling errors: "If your ridiculous pants are too loose, you're definitely going to lose them. Tell your two loser friends over there that they're going to lose theirs, too." It won't hurt your fashion sense, either. Last edited by yournamehere; 09-10-2003 at 08:15 PM..