Legos,lunch time,

and lollipops

Two-way Frequency Tables

Taking a first look at related data

Image used with Permission from Easyvectors.com

Let’s start with a little magic

This is a Magic Square

6 2

9

The challenge is to insert the numbers 1 – 9 in the squares, using each number only once. ***and***Every column, row, and diagonal must add up to the same total: 15. Like magic!

Try it on your own!!!

Understanding the magic

How did you figure out where to put each of the numbers?

6 2

9

Try to complete thismagic square on your own:

8 4

7

How did you decide where to put each number?

Connecting magic squares to “real-world” mathematics

Many times in real life, we need to look at a set of numbers and analyze how they are related to one another, similar to how we solved magic squares.

Using a table to organize the information is very helpful….

Rainy Day Fun

The Summer Camp for Kids staff is planning an indoor activity for the campers to do on rainy days. They are considering a Lego activity

and a finger painting activity. They send out a survey to all the kids

who will be coming to the camp to find out their preferences.

The staff organized the results of the survey in this table:

Legos painting total

boys 37 8 45girls 26 14 40total 63 22 85

A table like this that displays data in rows and columns is called

a two-way frequency

table.

What this two-way frequency table tells us

Legos painting total

boys 37 8 45girls 26 14 40total 63 22 85

1.How many boys preferred Legos?

2.How many girls preferred Legos?

3.How many campers preferred painting?

4.How many girls responded to the survey?

5.How many campers responded to the survey?

Vocabulary used with two-way frequency tables

legos painting total

boys 37 8 45girls 26 14 40total 63 22 85

The data in the middle of the table are called the joint frequencies.

The dataon the edges of the tableare called themarginalfrequencies.

Making a two-way frequency table

The Math Club is going to sell candy as a fund raiser. They surveyed 80 students about their favorite candy. The results are shown in the two-way frequency table. Fill in the missing information:

lollipop Peanut butter cups total

boys 19girls 43total 35

lollipop Peanut butter cups total

boys 19 18 37girls 26 17 43total 45 35 80

Lollipops, anyone???