1. Two Way Tables
Two Way Tables – Types of tables used to record and analyze the relationship between two or more categorical variables.
Categorical Variable – These are numbers that are collected in groups or categories.
Frequency – The number of times a value occurs within a set of data.

2. Class Data You will need a sheet of notebook paper (for notes).
You are going to see some pictures. Write down the first thing that you see.
No talking.
No changing your answer.

3. Man playing a saxophone or a silhouette of a woman?

4. Skull or woman at a table?

6. You are about to see another optical illusion.
You must write what you see first and not change your mind. 

8. Two way table Copy the chart below Girls Boys Total Rabbit Duck
How many girls saw a rabbit?
How many boys saw a duck?
What fraction of the class saw a rabbit?
What fraction of the class saw a duck?

9. Example 1
Felipe surveyed students at his school. His results are listed below.
He found that 78 students own a cell phone and 57 of those students own an MP3 player.
There are 13 students that do not own a cell phone, but own an MP3 player.
Nine students do not own either.

10. How many students own a cell phone and an MP3 player? __________
How many students own a cell phone but do not own an MP3 player? __________
How many students own a cell phone? __________
How many students do not own a cell phone and own an MP3 player? __________
How many students do not own either device? __________
How many students do not own a cell phone? __________
How many students own an MP3 player? __________
How many students do not own an MP3 player? __________
How many students did Felipe survey? __________