There are four balls in a hat: a blue one, a white one, and two red ones. Now I draw simultaneously two balls, look at them, and announce that at least one of them is red.

What is the chance that the other is red as well?

(In reply to There is only one correct answer !....SPOILER by Ady TZIDON)

This is a Baye's Theorem example.

Probability of B occurring when A is true.

Here is a similar example.  Let's say there is a disease that exists in 1% of the population.  There is a test for this disease that is 99% accurate (i.e. it gives a false reading 1% of the time).

If a random person tests positive for the disease, what is the probability that they have the disease?

Posted by hoodat on 2017-05-22 10:54:54