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Is the posterior really an update of our prior? That doesn't make any sense to me. It's P(A|B). I can't then use it as P(A) in another inference based on differ
by inciampati 7y ago
Is the posterior really an update of our prior? That doesn't make any sense to me. It's P(A|B). I can't then use it as P(A) in another inference based on different observations. What am I missing about your description of Bayesian inference?
- cgel 7y agoImagine you have two random variables A and B, which are 0 with prob 0.5 and 1 with prob 0.5. They just have the property that when A=1 then B is always 0 and vice versa. Thus, when you have seen the value of B, that clearly has changed the distribution of A. You should read P(A) as: the distribution of A when I know nothing about the world. And P(A|B=0) as: the distribution of A when I know that B took on value 0.