Investigation 11.4 Two-Way Frequency Tables

A Murder Mystery!

Cindy Jonuzaj | Mods 9, 10, 11 | Algebra 1

The Story

Alexandra Carry is a college student going to the Culinary Institute of America. She sadly passed away at approximately 9:34 A.M. on June 1st, 2021. Only the truest of friends would know about her love in math and her two-way frequency tables that were mysteriously missing from her apartment. She was planning to become the owner of a healthy breakfast, lunch, and dinner fast-food restaurant, that would provide food to schools all around her business. She used her love for math and made a two-way frequency table based on her own survey results. We are trying to track down the criminal by testing them on their ability to make a correct two-way frequency table. Alexsandra was a master at creating these tables and whoever else seems to be a master at this subject, is immediately our main suspect.

Alexandra

BUT… we sort of need help

We are trying our best to make sure that our information is correct, but we need another pair of eyes to be 100% sure. Are you willing to help us?

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No, Yes?

Well we are forcing you anyway! Come along now!

The Suspects

Cassandra

Tommy

Olivia

Information You Need to Know

(Vocab)

Two-Way Frequency Table - a way to display frequencies or relative frequencies for two categorical variables

• Each category is either represented by a row or a column
• Two-way frequency tables are especially useful when used to analyze survey results

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On the Right, you can see an example of a very well made two-way frequency table

Q. What are the categories in this two-way frequency table?

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Year/Grade & Chess/Art/Debate/Film or most likely Clubs

Information You Need to Know

(Vocab)

Relative Frequency - how often an event occurs divided by all outcomes

• Relative frequencies are written in either decimal or percentage form
• All the relative frequencies always add up to 1

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On the right is the example that was used on the previous slide.

Q. What is the relative frequency of kids who take chess?

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Q. What is the relative frequency of year 8 kids that take debate?

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22% or 0.22

Around 35.7% or 0.357

Make Your Own Two-Way Frequency Table

1. There are 19 students with chores who also have Curfews
2. There are 26 students with no chores but who also have Curfews
3. There are 23 students with no curfew but with chores
4. There are 17 students with no curfew but with no chores

Comparing You & The Suspects

• There are 12 college students and 9 high-school students who eat breakfast
• There are 14 college students and 15 high-school students who eat lunch.
• There are 21 college students and 29 high-school students who eat dinner

Our Completed Chart

Olivia’s Frequency chart

Tommy’s Frequency chart

Cassandra’s Frequency chart

Who is it?

Cassandra

Tommy

Olivia

Who is it?

Cassandra

Tommy

Olivia

Actual Real Life Situations

• “If you (state your gender) would watch a sporting event, which one would it be out of these three: Baseball, Basketball, or Football”

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• “If you (state your gender) would watch a program on TV, which program would it be based around out of these three: Dance, Sports, or Movies”

The End

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Thank you for listening!