Here goes the problem:
Suppose there is a disease that infects one in ten thousand people. Suppose a test procedure determines whether you have the disease with 99% accuracy--that is, if you have the disease there is a 1% chance of a false negative, and if you don't have the disease there is a 1% chance of a false positive. You took the test and the test result is positive. What is the probability that you have the disease?
The solution to the problem is---0.98%.
Now, here lies my confusion, if the test can detect my disease with 99% accuracy then shouldn't I have a 99% chance of having the disease? Probably, I am asking the dumbest question ever asked but I just can't work my intuition through this.