The phi coefficient is the equivalent of the correlation between
nominal variables. You compute it in SPSS for Windows in the *
crosstabs* procedure. We will illustrate it with the data from
Table 5.2.

Select the Analyze menu item, the Descriptive Statistics submenu item, and the crosstabs procedure, which will give you this screen. We want to look at the relationship between sex and political affiliation, so we move one of those variables into the rows section and the other into the columns section, as shown in this screen.

To compute Phi, we click on the statistics button and select Phi from the list of available statistics, as shown in this screen. Clicking continue returns you to the crosstabs box and clicking OK performs the computations. The results are shown on this screen, with the Phi coefficient and the associated probability value given in the box at the bottom.

In this case, the Phi coefficient is .45, with a *p*-value
of .088. Since the p-value is greater than the traditional value of
alpha (.05), we would fail to reject the null hypothesis and
therefore would conclude that we do not have evidence from this
sample that the distribution of political affiliations are different
in male and female populations.

We have prepared an animation that will walk you through this procedure. To run the animation, simply click on the title of the animation in the table below.

Note that we do not recommend that you try to run the animations if you have a slow connection, such as a dial-up connection. You will find that the animations take forever to load with a slow connection.