In that example, you're not calculating how many cavemen have apples. Rather you are calculating the probability, given that you are that a caveman has an apple, that is a real apple rather than a fake one.
So given a prevalence of 0.1 specificity of the test of 0.95 then a PPV around 0.65 seems about right. If your "test" detected an apple, there's about a 65% chance that it's really an apple.
In that example, you're not calculating how many cavemen have apples. Rather you are calculating the probability, given that you are that a caveman has an apple, that is a real apple rather than a fake one.
So given a prevalence of 0.1 specificity of the test of 0.95 then a PPV around 0.65 seems about right. If your "test" detected an apple, there's about a 65% chance that it's really an apple.
I guess I'm too retarded to wrap my head around 5/100 equating a 65% chance. I knew there was a reason I chose to stay out of professions that puts the lives of others in my hands. :D
I guess I'm too retarded to wrap my head around 5/100 equating a 65% chance. I knew there was a reason I chose to stay out of professions that puts the lives of others in my hands. :D