In the example for chain rule of probability, at 4:13,P(Bc | A) is given as 0.01. shouldn’t that be P(Bc Ո A)?
As per the statement, it says: the test shows negative result given that the person is infected.
Hence, it should be P(Bc|A).
As we already know that the person is infected. I guess the understanding for difference between both will become better as you proceed further.