Site US and Canada

Statistics: Chi-Square Tests
by Texas Instruments

Published on December 04, 2011


  • Students will recognize that chi-squared tests are for counts of categorical data.
  • Students will identify the appropriate chi-squared test to use for a given situation: X2 Goodness of Fit Test, X2 Test of Independence, or X2 Test of Homogeneity.
  • Students will learn how to calculate the degrees of freedom for each type of chi-squared test.
  • Students will interpret the results of a chi-square test.


  • alpha
  • categorical data
  • chi-squared (X2 distribution)
  • degrees of freedom
  • expected counts
  • goodness-of-fit test
  • observed counts
  • p-value
  • test of homogeneity
  • test of independence 

About the Lesson

This lesson involves investigating chi-squared tests and distributions.
As a result, students will:

  • Compare different scenarios and determine which chi-square test is appropriate.
  • Write the appropriate null and alternative hypotheses for the given scenario.
  • Determine the degrees of freedom for the chi-square test.
  • Look at chi-square test results and make the correct decision to reject or fail to reject the null hypothesis and write their conclusions in context.