Module 14: Background You’ll Need 4

  • Read and complete a contingency table

Organizing Categorical Bivariate Data

Contingency tables are used to quickly summarize and organize categorical bivariate data.

A teacher asks a group of [latex]11[/latex] students the following questions:

  • Do you have a driver’s license?
  • Do you own a bicycle?

The answers are recorded as follows:

  Driver’s License? Bicycle?
Student 1 Yes Yes
Student 2 Yes No
Student 3 No Yes
Student 4 No Yes
Student 5 Yes No
Student 6 No No
Student 7 No Yes
Student 8 Yes Yes
Student 9 Yes No
Student 10 Yes Yes
Student 11 No Yes

From looking at this table, it might be difficult to get a good sense of any patterns in the data set. The teacher decides to organize the information into a contingency table. Previously, you have used this tool to organize bivariate categorical data. In each cell, there is an integer representing a frequency or count.

Contingency tables are particularly useful when data sets are large.