Exercise Using SPSS to Explore Relationships Among Variables
Ed Nelson and Elizabeth Nelson, Department of Sociology
California State University, Fresno
RELG 3 Data
The Authors, 1998; Last Modified 05 September 2001
Note to the instructor: The data set used in this exercise is RELG9800 which is a combination of the 1998 and 2000 General Social Surveys. (Some of the variables in the GSS have been recoded to make them easier to use and some new variables have been created.) This exercise uses RECODE and CROSSTABS in SPSS to explore relationships among variables. In CROSSTABS, students are asked to use percentages, Chi Square, and an appropriate measure of association. Two-variable and three-variable relationships will be explored, along with the concepts of explanation, spuriousness, and replication. A good reference on using SPSS is SPSS for Windows Version 9.0 A Basic Tutorial by Richard Shaffer, Edward Nelson, Nan Chico, John Korey, Elizabeth Nelson and Jim Ross. To order this book, call McGraw-Hill at 1-800-338-3987. The ISBN is 0-07-241445-6 . There is an online version of the book at SPSS Text. You have permission to use this exercise and to revise it to fit your needs. Please send a copy of any revision to the authors.
Ed Nelson and Elizabeth Nelson
Department of Sociology
California State University, Fresno
Fresno, CA 93740
Please contact the authors for additional information.
Goals of Exercise
The goal of this exercise is to explore the relationship between religiosity and other variables using crosstabulation. This exercise will focus on two-variable relationships and then on three-variable relationships. The concepts of explanation, spuriousness, and replication will also be explored.
We’re going to use the General Social Survey (GSS) for this exercise. The GSS is a national probability sample of adults in the United States conducted by the National Opinion Research Center. For this exercise we’re going to use a data set that combines the 1998 and 2000 surveys. Your instructor will tell you how to access this data set.
Religiosity is the strength of an individual’s attachment to his or her religious affiliation. Several questions on the GSS are possible indicants of religiosity. One of the questions asks respondents to estimate the strength of their religious affiliation. This variable in the GSS is called RELITEN. Respondents were also asked how often they attend religious services (ATTEND) and how often they pray (PRAY). These are all possible indicants of religiosity, but we’re going to use ATTEND in this exercise.
The variable ATTEND has seven categories. Let’s start by reducing the number of categories. We’ll combine every week (value 7) and more than once a week (8) into one category and give this category a value of 1. Combine once a month (4), two to three times a month (5), and nearly every week (6) into another category and give this a value of 2. Finally, combine never (0), less than once a year (1), once a year (2), and several times a year (3) into another category and give this a value of 3. Now we have three categories--often (1), sometimes (2), and infrequently (3). Be sure to add value labels to make the output easier to read.
Let’s start by exploring the relationship between our measure of religiosity and whether or not respondents think pornography ought to be illegal to all or only illegal for those under the age of 18. The variable PORNLAW includes the respondents answers to the question "Which of these statements comes closest to your feelings about pornography laws? There should be laws against the distribution of pornography whatever the age. There should be laws against the distribution of pornography to persons under 18. There should be no laws against the distribution of pornography."
Use CROSSTABS in SPSS to get the crosstabulation of ATTEND and PORNLAW. Be careful when you select the independent and dependent variables. Be sure to select the correct percentages, Chi Square, and an appropriate measure of association. Write a paragraph or two describing the relationship between these variables using all this information.
We know that there are other variables related to ATTEND and PORNLAW. For example, other research has shown that women are more likely than men to attend church. Perhaps women are also more likely than men to feel that pornography ought to be illegal to everyone. Let’s see if we find these relationships in our data.
Use CROSSTABS to get the crosstabulation of SEX and ATTEND and the relationship of SEX and PORNLAW. Be sure to select the proper independent and dependent variables and to ask for the correct percentages, Chi Square, and an appropriate measure of association.
Write a paragraph or two describing the relationships you find. Were they what you expected to find?
Perhaps the reason that more religious people are more likely to feel that pornography ought to be illegal to all regardless of age is that women are more religious than men and women are also more likely to feel that pornography ought to be illegal to everyone. If this were true and we were to take the effect of gender out of the relationship, then we would expect the relationship between ATTEND and PORNLAW to disappear (or to be reduced considerably).
To check on this, let’s do a three-variable table. Your independent variable would be ATTEND; your dependent variable would be PORNLAW; your control (or test) variable would be SEX. Be sure to get the correct percentages, Chi Square, and an appropriate measure of association.
If the relationship between ATTEND and PORNLAW goes away for both men and women (or decreases sharply), then we would say the relationship was spurious and that we have explained away the relationship between religiosity and feelings about pornography laws. This is often referred to as explanation.
If the relationship between ATTEND and PORNLAW does not change when we control for sex, then we would say that we have replicated the relationship. The control variable has not affected the relationship between the independent and dependent variables. We call this replication because the relationship between ATTEND and PORNLAW has been replicated (or repeated) for both men and women.
Write a paragraph or two describing what you found when you controlled for gender. Use the percentages, Chi Square, and measure of association to help interpret your findings.