1. Two Way Tables Presented by Mr. Laws Allowance No Allowance Total
Chores 3 2 5
No Chores 1 4 8
Presented by Mr. Laws

2. Standard
8.SP.4 Use relative frequency to describe associations between variables:
Understand that patterns of association can also be seen in bivariate categorical data by displaying frequencies and relative frequencies in a two-way table.
Construct and interpret a two-way table summarizing data on two categorical variables collected from the same subjects.
Use relative frequencies calculated for rows or columns to describe possible association between the two variables.

3. Essential Question
How do I construct and interpret a two-way table summarizing data on two categorical variables ?

4. Key Vocabulary Words
Frequency – is the amount or a number of times that data appears in a data set.
Frequency Distribution – is a method used to group data into a meaningful pattern.
Relative Frequency (RF) – is the number of data written as a percentage (%).
Joint Relative Frequency (JRF)– is found by dividing a frequency that is not in the total row or total column by the grand total.
Marginal Relative Frequency (MRF)– is found by dividing a row total or a column total by the grand total.
Conditional Relative Frequency (CFA) – is found by dividing a frequency that is not in the Total row or the Total column by the frequency’s row total or column total.

5. What is a two-way table?
A two –way table is a table that displays two or more – variable data by organizing it into rows and columns.
Dog
No Dog
Total
Cat 6 4 10
No Cat 5 15 16 9 25

6. How do I create a Two –Way table?
Start with organizing a survey of two categories:
Student
Abby
John
Julie
Mike
Deb
Chris
Gus
Lynn
Chores
Yes No
Allowance
Create a two – way table based on the data you collected.
Allowance
No Allowance
Total
Chores
No Chores

7. What is a Relative Frequency (RF) Two – Way Table?
Allowance
No Allowance
Total
Chores 3 2 5
No Chores 1 4 8
Change the frequency data into relative frequency (%)
Allowance
No Allowance
Total
Chores
3/8 = 37.5%
2/8 = 25%
5/8 = 62.5%
No Chores
1/8 = 12.5%
4/8 = 50%
8/8 =100%

8. Two – Way RF table by Columns
Allowance
No Allowance
Total
Chores 3 2 5
No Chores 1 4 8
Allowance
No Allowance
Total
Chores
3/4 = 75%
2/4= 50%
5/8 = 62.5%
No Chores
1/4 = 25%
2/4 = 50%
3/8 = 37.5%
4/4 = 100%
8/8 =100%

9. Two – Way RF table by Rows
Allowance
No Allowance
Total
Chores 3 2 5
No Chores 1 4 8
Allowance
No Allowance
Total
Chores
3/5 = 60%
2/5= 40%
5/5 = 100%
No Chores
1/3 = 33%
2/3 = 67%
3/3 = 100%
4/8= 50%
4/8 = 50%
8/8 =100%

10. Summary Can you answer the essential question?
Do you have any additional questions pertaining to the lesson?
Is there any thing else you would like to know about this lesson?