Probability Formulae
Probability Formulas
1. Probability Range for an event A
\[ = 0 = P(A) = 1 \]
2. Rule of Complementary Events
\[ = P(A^c) + P(A) = 1 \]
3. Rule of Addition for events A and B
\[ P(A or B) = P(A) + P(B) – P(A \cap B) \]
4. Disjoint Events
Events A and B are disjoint
\[ <=> P(A\cap B) = 0 \]
5. Conditional Probability i-e probability of event A subject to event B
\[ P(\frac{A}{B}) = \frac{P(A\cap B)} { P(B)} \]
6. Baye’s Formula is
\[ P(\frac{A}{B}) = P(\frac{B}{A})\times \frac{ P(A)}{ P(B)} \]
7. Independent Events
Events A and B are independent if and only if
\[ P(A\cap B) = P(A) \times P(B) \]
