# Basic Bayes theorem question

What is the difference between "probability of H given E" as calculated by Bayes theorem and the "positive predictive value" of E?

We might do a test and come to the conclusion that it's indeed zero. However, we are never 100% sure, and we might have told that it's zero, but it's not, whenever this happens we have a false alarm. 1-(proportion of false alarms) gives you the positive predictive value, that is the proportion of times we don't have a false alarm in our test.