Module 1 Module 2 Investigation 2-1 Investigation 2-2 Investigation 2-3 Investigation 2-4 Investigation 2-5 Investigation 2-6 Investigation 2-7 Investigation 2-8 Investigation 2-9 Investigation 2-10 Module 3 Module 4 Module 5

#### 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:]
 Not animated.  Recommended for quick viewing. PDF: 710KB Not animated.  Recommended for printing. Animated viewing with Microsoft Internet Explorer. HTML Web file: 2,290KB Animated viewing with Netscape or other browser. PowerPoint file: 1,343KB

 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.