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Drawing Crayons

Unit 8 ● Lesson 7 ● Activity 1

A bag contains 1 crayon of each color: red, orange, yellow, green, blue, pink, maroon, and purple.

A person chooses a crayon at random out of the bag, uses it for a bit, then puts it back in the bag. A second person comes to get a crayon chosen at random out of the bag. What is the probability the second person gets the yellow crayon?
A person chooses a crayon at random out of the bag and walks off to use it. A second person comes to get a crayon chosen at random out of the bag. What is the probability the second person gets the yellow crayon?

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Warm-up

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Related Events

Unit 8

Lesson 7

Conditional Probability

GEOMETRY

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Unit 8 ● Lesson 7

I can estimate probabilities, including conditional probabilities, from two-way tables.

Learning

Targets

Geometry

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dependent events

independent events

Unit 8 ● Lesson 7

Dependent events are two events from the same experiment for which the probability of one event depends on whether the other event happens.

Independent events are two events from the same experiment for which the probability of one event is not affected by whether the other event occurs or not.

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Glossary

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Choosing Doors

Unit 8 ● Lesson 7 ● Activity 2

On a game show, a contestant is presented with 3 doors. One of the doors hides a prize and the other two doors have nothing behind them.

The contestant chooses one of the doors by number.
The host, knowing where the prize is, reveals one of the empty doors that the contestant did not choose.
The host then offers the contestant a chance to stay with the door they originally chose or to switch to the remaining door.
The final chosen door is opened to reveal whether the contestant has won the prize.

Choose one partner to play the role of the host and the other to be the contestant. The host should think of a number: 1, 2, or 3 to represent the prize door. Play the game keeping track of whether the contestant stayed with their original door or switched and whether the contestant won or lost.

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

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Choosing Doors

Unit 8 ● Lesson 7 ● Activity 2

Switch roles so that the other person is the host and play again. Continue playing the game until the teacher tells you to stop. Use the table to record your results.

Based on your table, if a contestant decides they will choose to stay with their original choice, what is the probability they will win the game?
Based on your table, if a contestant decides they will choose to switch their choice, what is the probability they will win the game?
Are the two probabilities the same?

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

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Tall Basketball Players

Unit 8 ● Lesson 7 ● Activity 3

A woman is selected at random from the population of the United States. Let event A represent "The woman is a professional basketball player" and event B represent "The woman is taller than 5 feet 4 inches."

Are these probabilities equal? If so, explain your reasoning. If not, explain which one is the greatest and why.

P(B) when you have no other information.
P(B) when you know A is true.
P(B) when you know A is false.

Are events A and B independent events or dependent events? Explain your reasoning.

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Lesson Synthesis

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