How-to Guide for IBM® SPSS® Statistics Software

Introduction

In this guide you will learn how to produce a frequency distribution in IBM® SPSS® Statistical Software (SPSS) using a practical example to illustrate the process. You are provided with links to the example dataset and are encouraged to replicate this example. An additional practice example is suggested at the end of this guide. The example assumes you have already opened the data file in SPSS.

Contents

- Frequency Distributions
- An Example in SPSS: Formats for TV News Stories in the United States
- 2.1 The SPSS Procedure
- 2.2 Exploring the SPSS Output

- Your Turn

1 Frequency Distributions

A frequency distribution presents the distribution of values for a single categorical variable in a table. Specifically, a frequency table reports the count and the percentage of observations there are for each category of the variable in question. Frequency distributions are very useful for describing the distribution of values for a categorical variable, and can be helpful in detecting coding errors.

2 An Example in SPSS: Formats for TV News Stories in the United States

This example presents a frequency distribution for a variable taken from the Pew Research Center’s Project for Excellence in Journalism News Coverage Index for 2012. There are 11,475 observations in the dataset. The specific variable is:

- The format of the news story that was broadcast (format), measured in mutually exclusive categories.

This variable has four categories: 8 = package, 9 = interview, 10 = staff live, and 12 = anchor read. This variable is categorical, making it appropriate for a frequency distribution.

2.1 The SPSS Procedure

A frequency distribution can be produced in SPSS by selecting from the menu:

Analyze → Descriptive Statistics → Frequencies

Figure 1 shows what this looks like in SPSS:

Figure 1: Selecting Frequencies from the Analyze menu in SPSS.

In the Frequencies dialog box that opens, move the variable you want from the list on the left into the Variable(s) box. In this case, the variable is named format, though it appears with its variable label “Story Format” (note: you can do this for multiple variables, producing a frequency distribution for each one). Figure 2 shows what this looks like in SPSS.

Figure 2: The Frequencies dialog box in SPSS.

If you wish to generate a bar chart to illustrate the contents of a frequency distribution graphically, then from the Frequencies dialog box, click “Charts …”. Then click the open circle next to “Bar charts” to produce a bar chart. Select either “Frequencies” or “Percentages” for the Chart Values. Figure 3 shows what this looks like in SPSS:

Figure 3: Generating a bar chart in SPSS.

To run the full analysis, click Continue, and then click OK in the Frequencies dialog box.

2.2 Exploring the SPSS Output

Executing this process for the variable format will produce one frequency table and one bar chart. Both contain the same information, but will suit different presentational purposes. Figure 4 presents the frequency distribution table and Figure 5 presents the bar chart.

Figure 4: Frequency distribution of TV news story formats, NCI 2012.

Figure 5: Bar chart illustrating the frequency distribution of TV news story formats, NCI 2012.

The figure includes a small table at the top that reports the sample size. Figure 4 shows that there were 3970 (34.6%) stories that were packages, 2705 (23.6%) that were interviews, only 1026 (8.9%) that were staff live stories, and 3774 (32.9%) that were read by the news anchor. Figure 5 presents the same information as a bar chart.

3 Your Turn

Download the sample dataset and see if you can replicate these results. Then repeat the process with the variable named focus, which measures the geographic focus of the news story in question.

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