500P
https://i.imgur.com/laGZC04.jpg
我的证明方法是
P(A|B) is the chance of A in condition of B.
P(A|-B) is the chance of A in condition of not B.
If the 2 values are the same, this indicates that regardless of B,
P(A) will be the same.
For P(A) = P(A|-B) = P(A|B), which prove that A and B are independent.
但没有算式好像有点丑
P(A|B) = P(A|-B)
P(A&B) / P(B) = P(A&-B) / P(-B)
要到 P(A|B) = P(A) 我爆不出来
太久没碰机率了 求救