Question

What are the basic rules of probability?

Answer 1

The basic rules of probability are given below.

Addition rule: $P(A\cup B)=P\left(A\right)+P\left(B\right)–P(A\cap B)$

This can also be written as $P(AorB)=P\left(A\right)+P\left(B\right)–P(AandB)$

Multiplication rule:$P(A\cap B)=P\left(A\right).P\left(\frac{B}{A}\right)$

When A and B are independent events, then $P(AandB)=P\left(A\right).P\left(B\right)$

Complementary rule: $P\left(A\right)+P(notA)=1$