Welcome to this tutorial on using spss to make sense of data. The example is about the impact of violent
programs on TV and display of aggressive behavior.
The example for this tutorial is on page 14 of the textbook "Essential of
statistics for behavioral sciences" and the textbook is by Gravetter
and Wallnau. Research question: "Is there a relationship between the amount of
violence the children see on television and the amount of aggressive behavior?"
(In this example) 18 kids are selected randomly from the population?
This is an (example of) experimental data ... experimental research design in which
one variable is whether the children watch or don't watch TV programs with violence
the variable one is "Violence" and
this variable has two values (1 and 2): the number one means that they watch TV programs with
violence, and number two
means that the children don't watch such programs. The secont variable, variable two is display of aggressive
behavior. The second variable is measures the number of aggressive instances. The values of this variable vary from zero to
four.
We will use the textbook data and spss. The goal is to enter data into SPSS then
we will let spss to organize and visualize the data for us. You know this
can happen with the click of a mouse or few clicks of our mouse. Then we will
make sense of this data.
In SPSS, first we will go in Variable View, and will enter our two variables. The first variable is
Violence on TV. The name of the variable is "Violence." The
label is "Violence on TV." As you know we use label for the variable, because the name name of the variable in SPSS should be only one word. This is
a string type of variable with two values. I will give values to numerical symbols:
1 means that the children are watching violent movies or
programs' and 2 means the children in the second group do not watch violent programs.
The first variable is ready. This variable this is controlled by the research
scientists. Researchers are controlling that children from the first group are watching violent programs, and
children from the second group are not watching violent programs. Researchers should not allow anything else to
interfere with this variable, which is the only one independent variable.
The second variable is "Aggression."
This is a numerical variable. The aggressive behavior ...
The variable is measured as a scale iin SPSS (interval/ratio level of measurement).
The two variables are identified in "Variable View."
In "Data View," I can use "1" for Violence, and I can copy the repetitive values.
On the key board, "Control C" will copy, and "Control + V" will paste the selected group of values.
Now let's enter the data for the second variable, Aggression. We have four values.
4, 2, 0, ...
Now i will form two groups. I will select all scores from the first group and will copy
and paste the scores in a new column, somewhere in here.
this is the group of children exposed to violent programs on TV. And then I willl copy the No Violence" group.
SPSS automatically forms two column, called "Variable 12" and "Variable 13."
Let's switch to "Variable View" and change "Variable 12" to aggression with violence
and "Variable 13" would be aggression with no violence.
so I split one variable in two groups.
In this case, the Violence on TV is a controlled or independent variable.
I will visualize the first group by Histogram - how many children have zero instances of violence, one instance, etc.
So, you can see that there are many children in this group who actually display more violent behavior (skew to the right),
which means a lot of aggression. Then, I will do graph the second group as a histogram. Let's see
the frequency distribution if kids don't watch violent programs.
So the children who are not exposed to violent programs on TV have much less
violent behavior.
i will copy these hystograms. Control C copy and will place it in PowerPoint (Control V). Immediately you can see
that very few children from who do not watch violent programs have high level of aggressive behavior. (left graph).
We can see there is difference between the two histograms.
Children who do not watch violent programs on TV do not display violent behavior.
Children who watch violent programs, display more instances of violent behavior.
