GATE Notes,
Probability Formulas
Probability Range
0 ≤ P(A) ≤ 1
Rule of Complementary Events
P(Ac) + P(A) = 1
Rule of Addition
P(A∪B) = P(A) + P(B) – P(A∩B)
Disjoint Events
Events A and B are disjoint iff
P(A∩B) = 0
Independent Events
Events A and B are independent iff
P(A∩B) = P(A) ⋅ P(B)
Conditional Probability
P(A | B) = P(A∩B) / P(B)