Descriptive Statistics

Basic SPSS Functions

1. Frequencies, Descriptives, Histograms

In working with data, a typical first step is to compute frequencies for all categorical variables and to compute descriptive statistics for all continuous variables. Also, creating histograms for continuous variables is a nice first step. In this first section, where you’re learning these skills, it might be helpful if you choose specific variables from your own data set to analyze.

Here’s how to do all this fun stuff:

The “frequencies” command in SPSS lets you know how common different values of a categorical variable are in the sample. For instance, you can use this command to determine how many males and females (in a variable, perhaps, called “gender”) were included in your sample. To compute frequencies, do the following:

A. Choose a categorical variable.
B. When in data view, click on “analyze,” then “descriptive statistics,” then “frequencies.”
C. Choose the appropriate categorical variable to put in your variables list.
D. Then click “paste” to put the command in a syntax file.
E. Run that part of the syntax file.

The “descriptives” command provides information about continuous variables. For instance, you can obtain information about the range of scores, the mean of the variable, the standard deviation, and the number of cases. To compute this command, do as follows:

A. Choose a continuous variable.
B. When in data view, click on “analyze,” then “descriptive statistics,” then “descriptives.”
C. Choose the appropriate continuous variable to put in your variables list.
D. Then click “paste” to put the command in a syntax file.
E. Run that part of the syntax file.

The “histogram” command provides a graph of how common each score is for a continuous variable. This graph can, for one, give you a sense of whether your variable is normally distributed. To run this command, do as so:

A. Choose a continuous variable.
B. When in data view, click on “graphs,” then “legacy dialogs,” then “histogram.”
C. Choose the appropriate continuous variable to put in your variables list.
D. Then click “paste” to put the command in a syntax file.
E. Run that part of the syntax file.
F. Look at your beautiful graph!

2. Frequencies, Descriptives, Histograms for data measured in class.

For this part, you need to collect data from the people in lab on one continuous variable and one categorical variable. You will collect these data as a group (i.e., the whole class will agree on the variable to be measured). An example of the continuous variable could be height (in inches); an example of the categorical variable could be gender (male or female). Collect data from everyone in the lab. Next you will analyze these data and type up a brief lab report.

A. The continuous variable.

For this variable, you will use SPSS to compute descriptive statistics. In your report, indicate the range, mean, standard deviation, and N for this variable. Next, use SPSS to create a histogram for this variable. Briefly summarize this histogram and include the SPSS output (as an attachment) with both the summary of the descriptives and the histogram.

B. The categorical variable.

For this variable, you will use SPSS to compute frequencies. Simply summarize the frequency of different values in your report. Also include the SPSS output for the frequencies command as an attachment. If you have anything interesting to say about these results, outline these points in your report.

What to hand in:
1. Your report summarizing (a) what variables were examined and (b) the results regarding these analyses.
2. A printout of the syntax file(s) for all commands.
3. A printout of the data file(s).
4. A printout of the output file(s).