Section 1.3

Conditional Probability and Intersection of EventsSection 13.3ObjectiveFind the probability of one event and a second event occurring.

Compute conditional probabilities.

Key Term:Conditional Probability the probability of event B, assuming that event A has already occurred, We denote this probability by P(B/A).

Independent Events two events that their occurrence has no effect on the probability of the other.

Dependent Events two events that their occurrence has an effect on the probability of the other.Key Concept:Special Rule for Computing P(F/E) by Counting

If E and F are events in a sample space with equally likely outcomes then

P(F/E) = n(E F) = number of outcomes common to E and F n(E) number of outcomes in EKey Concept:General Rule for Computing P(F/E)

If E and F are events in a sample space with equally likely outcomes then

P(F/E) = P(E F) P(E)Example 1: Compute P(F/E)TB pg. 754/5Example 2: Compute P(F/E)TB pg. 754/7Example 3: Find the probability

TB pg. 754/11Example 4: Compute P(E/F) and P(F/E)

TB pg. 754/15Example 5: Find P(F/E)

TB pg. 755/17

Example 6: Find P(F/E)

TB pg. 755/19

Example 7: TB pg. 755/33Example 8: TB pg. 755/37

Example 9: TB pg. 755/43Key Concept:And Probabilities with Independent Events

If A and B are independent events, then

P(A and B) = P(A) * P(B).

And Probabilities with Dependent Events

If A and B are dependent events, then

P(A and B) = P(A) * P(B given that A has occurred).15Example 10: TB pg. 755/47Example 11: TB pg. 756/51Example 12:TB pg. 756/55Section 13.3 AssignmentClasswork:TB pg. 754/6 20 Even, and 34 56 EvenRemember you must write problem and show ALL work to receive credit for this assignment.DUE Tuesday, 11/ 22/11