A Test of Your Skills

1% of women at age forty who participate in routine screening have breast cancer. 80% of women with breast cancer will get positive mammographies. 9.6% of women without breast cancer will also get positive mammographies. A woman in this age group had a positive mammography in a routine screening. What is the probability that she actually has breast cancer?

It may seem like a simple math/statistics problem on the surface – and to be fair, it kinda is – but only 15% of medical professionals get the answer correct.

[PS this is not a riddle, no word-play here. This is a sort of a poll I’m taking on ILP. Please do not cheat, avoid looking around on the internet or on the answers in this thread, just use the information given and whatever math/statistics knowledge you have to figure out the answer.]

7.8% likelihood that she actually has breast cancer

Voila

Well, you did say that cutting to the chase is faith. We wouldn’t want that.

Post some more and I’ll keep quiet.

Edit your last post and someone else is bound to give the problem a try.

perhaps…

I actually got the wrong answer the first time I tried it, but then I read the next sentence in the website where I got the problem, and it said “Most doctors get it wrong,” and I rethought my logic and realized i made a mistake.