Links to posts on Bayesian probabilityAn easier method for probabilities of false positives and false negatives

Here are the previous posts about Bayesian probability, which in our case means we want to understand the different between the probabilities of false positive tests and false negative tests.

In class we used a contingency table method to find the probabilities of false negatives and false positives. This is useful if we want to work with doing a second sample, as we did when the false positive probability was so high. If we just want to find probabilities on a single test, here is an easier method.

e = error rate and a = accuracy rate, where e + a = 1
p = proportion of trait in the population and q = 1 - p

probability of a false positive = eq/(eq + pa)

probability of a false negative = ep/(ep + qa)