Page 177 - Math Course 1 (Book 2)

Probability and Composite Events

Mo. 11

Lesson 8 dependent events

the outcome of one event affects the outcome of a
second event.

KEY CONCEPTS: 2 red and 2 white chips in a box.
1. Find the probability of independent and
dependent events. Pick 1, write down the color and
do not put back in the box.
2. Find the probability of mutually exclusive
events. Pick 1 again, write down the
color and do not put back in the
box.
MO. 11 - L8a
mutually exclusive events
Independent, Dependent, and two events that cannot happen at the same time.

Mutually Exclusive Events
6 1
The spinner cannot stop on
both blue and an even
Vocabulary A-Z number at the same time 5 2
Let us learn some vocabulary 4 3

Concept Summary

composite events (aka compound events) Probability of Two Independent
A composite event consists of two or more simple
events. Events
Words The probability of two independent
2 red and 2 white chips in a box. events is found by multiplying the
probability of the f rst event by the
Pick 1, write down the color and probability of the second event.
put back in the box.

Symbols P(A and B) = P(A) • P(B)
Pick 1 again, write down the
color and put back in the box.
1 1 1
Example P(red and white) = 2 • 2 or 4
independent events
the outcome of one event does not inf uence the
outcome of a second event. Key Summary

Probability of Two Dependent

Events
Toss a die.
Words If two events, A and B, are dependent,
then the probability of both events
Toss a die again.
occurring is the product of the
probability of A and the probability of B
after A occurs.
Symbols P(A and B) = P(A) • P(B following A)

Example P(red and white, without replacement)
1 2 1
= • or
2 3 3

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