Lesson 12-9 Pages 650-655

Probability of Compound

Events

What you will learn!1. How to find the probability of independent and dependent events.

2. How to find the probability of mutually exclusive events.

Compound eventsCompound eventsIndependent eventsIndependent eventsDependent eventsDependent eventsMutually exclusive Mutually exclusive eventsevents

What you really need to know!

Probability Probability of Two of Two

IndependenIndependent Eventst Events

Found by multiplying Found by multiplying the probability of the the probability of the first event by the first event by the probability of the probability of the second eventsecond event

P(A and B)P(A and B)

= P(A) = P(A) • P(B)• P(B)

What you really need to know!

Probability Probability of Two of Two

Dependent Dependent EventsEvents

Is the product of the Is the product of the probability of A and probability of A and the probability of B the probability of B after A occursafter A occurs

P(A and B) =P(A and B) =

P(A) P(A) • P(B following • P(B following A)A)

What you really need to know!

Probability Probability of Mutually of Mutually Exclusive Exclusive

EventsEvents

Found by adding the Found by adding the probability of the first probability of the first event to the event to the probability of the probability of the second eventsecond event

P(A or B) =P(A or B) =

P(A) P(A) + P(B)+ P(B)

Example 1:

In a popular dice game, the highest possible score in a single turn is a roll of five of a kind. After rolling one five of a kind, every other five of a kind you roll earns 100 points. What is the probability of rolling two five of a kinds in a row?

Example 1:

These events are independent. Each roll of the dice does not affect the outcome of the next roll.

When rolling 5 die, there are 65 possible outcomes. 7,776.

There are 6 ways to get 5 of a kind.

Example 1:

The probability of rolling one 5 of a kind is 6 : 7,776 which means 1 : 1,296

Two in a row would be:

616,679,1

1

296,1

1

296,1

1

Example 2:

Charlie’s clothes closet contains 3 blue shirts, 10 white shirts, and 7 striped shirts. What is the probability that Charlie will reach in and randomly select a white shirt followed by a striped shirt?

Example 2:

These events are dependent. The selection of the first shirt reduces the number of shirts to pick from.

20

1010 white shirts

20 shirts in all

7 striped shirts

19 shirts left

19

7

38

7

Example 3:

You draw a card from a standard deck of playing cards. What is the probability that the card will be a black nine or any heart?

Example 3:

The events are mutually exclusive because the card can not be both a black nine and a heart at the same time.

52

13

52

2

2 black nines

52 cards in deck

13 hearts

52 cards in deck

52

15

Page 653

Guided Practice

#’s 4-10

Pages 650-652 with someone at home and

study examples!

Read:

Homework: Pages 653-655

#’s 11-18, 21-28,

33, 34, 36-50

Lesson Check 12-9

Page

755

Lesson 12-9

P(13 or even)

Study Guide and Review

Pages

658-662

#’s 1-30 or 19-30(Odd answers in back of book)

Prepare for Test!

Page 663

#’s 1-20 or 10-20

Lesson Check 12-9

Prepare for Test!

Pages

664-665

#’s 1-19