1. The document is an introduction to probability that includes examples of experiments with outcomes and events along with definitions of key probability terms. 2. It discusses sorting a list of events from least to most likely when rolling a number cube and calculating probabilities for different scenarios like picking marbles from a bowl. 3. The document also defines the complement of an event as the set of all outcomes not included in the original event and explains how the probability of an event plus the probability of its complement equals 1.

1. Intro to Prob .notebook March 18, 2013
AIM: Introduction to Probability
Do Now
The ratio of the length of Tom's rope to
the length of Jan's rope was 3:1. The
ratio of the length of Maxwell's rope to
the length of Jan's rope was 4:1. If Tom,
Maxwell, and Jan have 80 feet of rope
altogether, how many feet of rope does
Tom have?
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2. Intro to Prob .notebook March 18, 2013
Rolling a Number Cube (A Fair Die)
On Core
When a number cubed is rolled Page 157
once the possible numbers that
could show up are?
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3. Intro to Prob .notebook March 18, 2013
Below is a list of 9 different Events
Directions: With your partner order the events from
those least likely to happen to the ones that are most
likely to happen when you roll a number cube.
Rolling an 8
Rolling a number greater than 5
Rolling a 5
Rolling an even number
Rolling an odd number
Rolling a prime number
Rolling a 1, 2, or 3
Rolling a number other than 6
Rolling a number less than 7
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4. Intro to Prob .notebook March 18, 2013
Reflect:
1a.) Explain how you sorted your events?
1b.) Are any of these events impossible?
Probability Continuum
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5. Intro to Prob .notebook March 18, 2013
Experiment- Is an activity involving chance in which the
results are observed
Trial- Each observation in an experiment.
Outcome- Each result
Probability: The probability of an even is written
p(event), measures the likelihood that the event
will occur.
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6. Intro to Prob .notebook March 18, 2013
Probability is a measure between 0 and 1, as shown in the
number line below.
The probability can be written as a fraction, a decimal, and
a percent.
Probability Continuum
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7. Intro to Prob .notebook March 18, 2013
Describing Events
Determine whether each event is impossible, unlikely, as
likely as not, likely, or certain. Then, tell whether the
probability is 0, close to 0, 1/2, close to 1, or 1.
A.) You flip a coin. The coin lands heads up.
B.) You roll two number cubes and the sum of the numbers
is 10.
C.) A bowl contains 14 red marbles and 3 green marbles.
You pick a red marble.
C.) A spinner has 10 equal sections marked 1 through 10.
you spin and land on a number greater than 0.
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8. Intro to Prob .notebook March 18, 2013
Try This!
Describe each event as impossible, unlikely, as likely as
not, likely, or certain. Tell whether the probability is 0,
close to 0, 1/2, close to 1, or 1.
2a.) A hat contains pieces of paper marked with the
numbers 1 through 16. You pick an even number.
2b.) A spinner has 6 equal sections marked 1 through 6. You
spin and land on zero.
REFLECT
2c.) The probability of event A is 1/3. The probability of
event B is 1/4. What can you conclude about the two
events?
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9. Intro to Prob .notebook March 18, 2013
Complement of an Event
Complement of an Event = is the set of all outcomes not
included in the event. For example, consider the event
that you roll a number cube and get a 3. The compliment
is the event you do not roll a 3. The compliment is rolling
1,2,4,5 or 6.
The sum of the probabilities of an event and its
complement equals 1.
p(event) + p(complement) = 1
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10. Intro to Prob .notebook March 18, 2013
In a standard deck of cards, the probability of
choosing a card at random and getting an ace is
1/13. What is the probability of not getting an
Ace?
p(event) + p(complement) = ______
p(ace) + p(___________) = 1
p(not getting an ace) = 1 -
=
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11. Intro to Prob .notebook March 18, 2013
Try This!
A jar contains balls marked with the
numbers 1 through 8. The probability
that you pick a number at random and
get a 5 is 1/8. What is the probability
of not picking a 5?
You roll a number cube. The probability
that you roll an even number is 1/2.
What is the probability you will roll an
odd number?
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12. Intro to Prob .notebook March 18, 2013
Reflect
Why do the probability of an event and the probability of
its compliment add up to 1?
Give an example of a real-world event and its complement.
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13. Intro to Prob .notebook March 18, 2013
Homework
On Core Page 160 #1-10 all
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