Lesson 45: Contingency Tables

Printer-friendly versionPrinter-friendly version

milk cartonIntroduction

In this lesson, we'll investigate two more applications of the chi-square test. We'll first look at a method for testing whether two or more multinomial distributions are equal. This method is often referred to as the test for homogeneity.  (Homogenized milk... get it?)

We'll then look at a method for testing whether two or more categorical variables are independent. This test is often referred to as the test for independence. It allows us to test for independence of, say, an individual's political affiliation and his/her preference for a particular presidential candidate.

Objectives

  • To learn how to conduct a test for homogeneity.
  • To learn how to conduct a test for independence.
  • To understand the proofs in the lesson.
  • To be able to apply the methods learned in the lesson to new situations.