# Two-Way Tables

Related Topics:
Common Core for Grade 8
Common Core for Mathematics
More Math Lessons for Grade 8

Videos, examples, solutions, and lessons to help Grade 8 students 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.

For example, collect data from students in your class on whether or not they have a curfew on school nights and whether or not they have assigned chores at home. Is there evidence that those who have a curfew also tend to have chores?

Common Core: 8.SP.4

### Suggested Learning Targets

• I can recognize patterns shown in comparison of two sets of data.
• I can show how to construct a two-way table.
• I can interpret the data in the two-way table to recognize patterns. (For examples, collect data from students in your class on whether or not they have a curfew on school nights and whether or not they have assigned chores at home. Is there evidence that those who have a curfew also tend to have chores?).
• I can use relative frequencies of the data to describe relationships (positive, negative, or no correlation).
What is Bivariate Categorical Data?
Data can be classified two major groups: Qualitative Data and Quantitative Data.
Qualitative describes and quality. Quantitative describes "how much".
What is Categorical data?
Categorical data is data that described an attribute, or quality. Categorical data is qualitative data because it described a quality.We think of this type of qualitative data as being placed into categories, or groups.
What is Bivariate data?
Bivariate data means we have taken two different measurements from the same object.
How to Create Two-Way Tables From Bivariate Categorical Data?
Analyzing Two-Way Tables From Bivariate Categorical Data

Summarizing Bivariate Data
Example:
A study was conducted to determine whether or not people who are allergic to animals have pets. The results are recorded in the table.
(a) How many people were surveyed?
(b) How many people are allergic to animals and have a pet?
(c) How many people are not allergic to animals and do not have a pet?
(d) How many people surveyed were allergic to animals?
(e) How many people surveyed have pets?
Two-way Tables: Creating and Completing
How to create and complete two-way tables.
Showing data in a two way table.
Examples:
A survey was carried out asking adults and children whether or not they owned a tablet. The following two-way table represents the answers given.
Another survey was carried out. This time we ask people who have a tablet. We ask them whether it is an iPad or a different brand.