Investigation 2-1
The 2 X 2 Table

Synopsis

Students examine the results of a hypothetical study to determine if a medication prevents acne.  In doing so, students uncover that a scientific study needs to examine not only people who are exposed to the medication, but also a group of people who are not exposed to the medication.  Students construct 2x2 tables and realize that when they study how an exposure and an outcome (disease) are distributed, every person in the study population fits into one of the four cells of the 2x2 table.  Students also realize that the way an exposure and an outcome are distributed in a group of people can be expressed mathematically.

Investigation Preparation Checklist

Check alignment with standards.

National or State file

Review Epidemiology Background for Module 2.

Word or PDF file

Review teacher's notes and slides:  [en espaņol:]

Copy Epi Talk handout for each student.

Word or PDF file

Copy Investigation 2-1: Epi Log Worksheet for each student.  [en espaņol:]

Word or PDF file

Review Investigation 2-1: Epi Log Worksheet Answer Key

Word or PDF file

Estimated Time / Time Management

Approximately one class period. Time can be managed by increasing or decreasing the number of 2X2 rate and risk calculations or cell identifications.

Look For Students To:

	Construct a 2x2 Table.
	Describe the components and use of a 2x2 Table.
	Identify the cell or cells in the 2x2 Table in which groups of people belong.
	Express the exposure and disease mathematically.