1. CHI-SQUARE TEST OF INDEPENDENCE
What Is the Purpose?
What Are the Assumptions?
How Does it Work?

2. What is the Purpose? Test whether two nominal variables are related.
Use for a design in which individuals categorized in two ways.
Null hypothesis is that the two variables are unrelated.

3. What are the Assumptions?
Mutually exclusive groups
Expected frequencies at least 5 per cell

4. How Does it Work?
Determine the frequencies you expect if the Ho is true.
These expected frequencies are based on the Ho: the frequency distribution for one variable is not different for different levels of the other variable.

5. How Does it Work?
Compare the observed frequencies to the Ho expected frequencies.
Large differences between observed and expected give a large value of chi-square, likely to be significant.