.

##### Probability – Notes

**Conditional Probability**

If A and B are two events of the same sample space S, then the conditional probability of event A, given that even B has occurred, is given by

P (AôB) = , ¹ 0.

If A is an event associated with sample space S, then P (SôA) = P (AôA) = 1.

If A and B are two events of the same sample space S, and E is an event of S such that ¹ 0, then )ôE) = P (AôE) + P (BôE) – )ôE).

A and B are two events of the same sample space S, then P (A’ôB) = 1 – P (AôB).