A1 and A2 seem be independent, but the calculation shows
P(A2|A1) ≠P(A2) P(A1)
My question is why it is the case, are there any methods to know that they are independent without calculation?
更新1:
are there any methods to know that they are independent or not without calculation?
更新2:
P(A2 ∩ A1) ≠ P(A2) P(A1) 才是正確