Did the Doctor
make the correct medical diagnosis?
Consider the following
problem
"One
in a thousand people has a prevalence for a particular heart disease.
There is a test to detect this disease. The test is 100%
accurate
for people who have the disease and is 95% accurate for those who don't
(this means that 5% of people who do not have the disease will be
wrongly diagnosed as having it).
If a randomly selected person tests positive what is the probability
that the person actually has the disease?"
This question was put to
60 students and staff at Harvard Medical School.
Almost half gave the
response 95%.
The 'average' answer was
56%.
In fact, the correct
answer is very different and was given by just
11 participants.
Click here
for the answer and an explanation.
