> What is a “prior” in the context of hypothesis testing? A prior could be any previous knowledge that you have on the subject, or anything about the world. L

> What is a “prior” in the context of hypothesis testing? A prior could be any previous knowledge that you have on the subject, or anything about the world. Let me give you a silly example. Imagine I do an experiment, on if person A can see the future, and predict coin flips. Now, imagine that I do this experiment, and lo and behold it passes the 5% threshold P value! Remember what a P value is. It is simply the percent chance that the results that you got were by chance. So, if I do that experiment, and it actually gets at the "P value" of 5%, which means that there is a 5% chance of it happening by chance, do you know believe that Person A can see the future? I wouldn't. I would need a much lower P value to start believing that. Thats all a prior is. It is using the fact that "Person A can see the future!" is an extraordinary claim. And for that, we require extraordinary evidence. Much better evidence than a mere "5% that it happened by chance". P