Using SPSS to Understand Research and Data Analysis.

3.2 Interpreting the Frequencies Procedure Output

The results of this procedure will now appear in an SPSS Output Viewer window (Figure 3.13).

The first information in the output is the Statistics table. This table displays how many valid cases (N) were processed and how many cases had missing values for each of our variables. Since we have no missing values, the number of valid cases is the full 10 students for both variables.

Note: Rather than showing the entire viewer window as we discuss various parts of output files, hereafter we will display different parts of the output as separate figures. The next table is the simple frequency distribution for the variable, sex (Figure 3.14). To find this table, just scroll down your output viewer window to find this table, or click that item in the tree menu in the left pane.

The first column lists the labels we assigned to the two levels of this variable (1: male; 2: female). The Frequency column displays the frequency of each score (in this case, category). This shows that of the ten students, five were women and five were men. These frequencies are converted to percentages in the Percent column (50% men, 50% women). Note the Valid Percent column shows the same values. These would be different if we had missing data; i.e., this column adjusts the percentages based on missing values.

Scroll down your output and you will see the bar chart we generated for this variable (Figure 3.15).

This lists the numerical values of the variable (1: male; 2: female) on the horizontal axis and the frequencies (how many instances of each sex) on the vertical axis. This visual depiction of the results clearly shows an equal number of men and women, with the two bars of the chart being the same height.

Scroll back up to see the next table presenting the distribution of scores on the courses variable (Figure 3.16).

In this table, the scores in the first column are the number of psychology courses taken by the students. Thus, students had taken between 1 and 4 courses prior to statistics.

The Frequency column shows how many students had 1, 2, 3 or 4 courses. Thus, two students had taken 1 course, three had taken 2 courses, four had taken 3 courses, and one had taken 4 courses.

Again, these frequencies are converted to percentages in the Percent column. From this inspection, we can conclude the most students had taken either 2 psychology courses (30%) or 3 (40%) courses.

Scroll down and you will see the bar chart of this frequency distribution (Figure 3.17).

The bar chart again provides a visual depiction of this distribution. A glance at this graph clearly shows that the most frequent number of courses taken by students prior to taking statistics was 3, followed by 2 courses.