Practicing Success
Let 0 < P(A) < 1, 0 < P(B) < 1 and P(A ∪ B) = P(A) + P(B) - P(A)P(B). Then: |
P(B/A) = P(B) - P(A) P(Ac ∪ Bc) = P(Ac) + P(Bc) P(A ∪ B)c = P(Ac) + P(Bc) P(A/B) = P(A) |
P(A/B) = P(A) |
P(A ∪ B) = P(A) + P(B) - P(A).P(B) ⇒ P(A ∩ B) = P(A).P(B) $⇒P(A/B)=\frac{P(A ∩ B)}{P(B)}= P(A)$ |