
Doctors flunk quiz on screening-test math (2014) - respinal
https://www.sciencenews.org/blog/context/doctors-flunk-quiz-screening-test-math
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DanBC
This is an interesting article. If you like this kind of thing you might enjoy
books by Gerd Gigerenzer.

I find the article's use of percentages frustrating. We know people find it
hard to understand percentages, so this article should give the question twice
- the first using percentages and the second using natural frequencies.

"A machine has been invented to scan a population for a disease. The machine
is good but not perfect. If you have the disease there is a 90% chance it will
return positive. If you do not have the disease there is a 1% chance it will
return positive. About 1% of the population have the disease. Mr Smith is
tested, and the test comes back positive. What's the chance Mr Smith actually
has the disease?"

(This is from "Reckoning with Risk" by Gerd Gigerenzer).

Most people cannot get the right answer from this question.

If you reword the question they can.

"Think of a group of 100 people. 1 of them has a disease. The entire group is
screened. The one person who has the disease tests positive. Of the 99 people
who don't have the disease one person will also test positive. How many people
of those who test positive have the disease?"

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respinal
Have you read ‘Rationality for Mortals: How People Cope with Uncertainty
(Evolution and Cognition)’ by Gerd Gigerenzer? Looks very interesting.

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DanBC
I haven't read that. I've read _Reckoning with Risk_ and _Risk Savvy_.

Risk Savvy is later and better because he's had time to refine the ideas.

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respinal
I just have watched some of his TED talks and I am hooked! Thanks again!

