9.1 Mini Lesson: Probability of Simple Events

Mini Lesson:

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Probability of Simple Events

📰 READ the informational slides and ✅complete the questions that follow.

VOCABULARY >>>

📰 Simple Event =

has one outcome OR one collection of outcomes

📰 Outcome =

possible result in an event (probability experiment)

​example: you roll a die ​

​

​These are the 6 possible outcomes:

📰 Probability =

A ratio that compares the number of wanted outcomes to the number of possible (total) outcomes

Multiple Choice

Which notation is the short way to write "the probability of rain today" ?

• P(rain today)

• prob(rain today)

• Pr(rain today)

📰 Probability can be written as a

FRACTION, DECIMAL, or PERCENT

Multiple Choice

Which event is certain (100% chance of happening) ?

• There will be a rainbow this week.

• The sun will set today.

• You will grow an extra arm.

Multiple Choice

Classify the probability of the event: You will grow an extra arm.

• 50% = Equally likely as unlikely

• 0% = Impossible

• 25% = Unlikely

• 100% = Certain

EXAMPLES & You Try Questions

>>>

Example 1: A die with sides labeled 1-6 is rolled, find the probability of rolling a 6

• P(6) as a ratio =

​wanted

total​

​O

Multiple Choice

YOU TRY #1: A coin is tossed, find the probability of the coin landing on heads.

wanted/total

• P(heads) = 1/4 = 25%

• P(heads) = 1/2 = 50%

• P(heads) = 1/1 = 100%

• P(heads) = 1/6 = 17%

Example 2: Find the probability of rolling a 2, 3, or 4 on a number cube.

• wanted/total

• number cube has 6 possible outcomes; 1, 2, 3, 4, 5, 6

• we want the P(2, 3, or 4) which are three of the six possible outcomes

​O

​O

​O

Multiple Choice

A student is randomly chosen. What is the probability that the student chosen has a first name that starts with a vowel?

Simplify if needed!

• 1/4

• 0/8

• 3/4

• 3/16

• 3/8

Multiple Choice

A student is randomly chosen. What is the probability that the student chosen has a first name with less than 6 letters?

Simplify if needed!

• 5/8

• 0/8

• 3/4

• 1/2

• 3/8

Multiple Choice

A student is randomly chosen. What is the probability that the student chosen has a first name that starts with the letter B?

Simplify if needed!

• 1/8

• 0/8

• 3/4

• 1/4

• 3/8

Multiple Choice

You reach into this mini M&M bag and choose one M&M without looking. What is the probability of choosing a green M&M?

P(green) =

• 9/9 = 1

• 4/9 = 0.4444...

• 1/9 = 0.1111...

• 0/9 = 0

Multiple Choice

You reach into this mini M&M bag and choose one M&M without looking. What is the probability of choosing a yellow M&M?

P(yellow) =

• 9/9 = 1

• 4/9 = 0.4444...

• 1/9 = 0.1111...

• 0/9 = 0

Multiple Choice

What is the probability of randomly choosing a yellow skittle? *Simplify!*

P(yellow) = yellow/total =

• 5/10

• 5

• 1/2

• 1/3

• 6/15

Multiple Choice

What is the probability of randomly choosing a skittle that is NOT purple? *Simplify if needed!*

P(not purple) =

• 14

• 14/15

• 1/14

• 1/15

Multiple Choice

Which wheel spinner is the BEST choice if you want to win?

• Wheel A because you are more likely to win (than lose.)

• Wheel B because you are more likely to win (than lose.)

• Wheel C because you are more likely to win (than lose.)

• All the wheels have an equal chance of winning and losing.

Multiple Choice

You are going to spin the wheel. Is this a fair game?

• It is fair; there is an equal chance of winning and losing.

• It is not fair; there is a higher chance of winning than losing.

• It is not fair; there is a higher chance of losing than winning.

Multiple Choice

You spin the wheel. What is the probability that it will land on an even number?

P(even) =

• 2/5

• 5/5

• 1/5

• 3/5

Multiple Choice

You spin the wheel. What is the probability that it will land on an odd number?

P(odd) =

• 2/5

• 5/5

• 1/5

• 3/5

Open Ended

Each wheel spinner is divided into equal sections. You can choose one wheel to spin once. The number it lands on represents the number of candy you win. Which wheel would you choose and why?

Open Ended

Last slide! What did you think of this topic/lesson?