00:01
So first, what exactly is base theorem? well, base theorem is a probability rule.
00:05
Recall conditional probability probability of a happening given that b happens, is the probability that both happen over the probability that b happens.
00:15
Another way to write the probability of a given b, this is equivalent to the probability of a happening times the probability of b given a happening.
00:25
Okay, so this is kind of inverse conditional probability.
00:29
So if a given b given a times the probability of a.
00:33
All over, there's two cases for the probability of b happening.
00:37
Probability of a and b happening plus the probability of a of not a and b happening.
00:45
So in this case, if this breaks down, a times the probability of b given a, probability of a and b, we already did that probability of a times the probability of b given a...