Quantitative researchers study relationships among two or more variables.
As the name suggests, variables are things that are different or are expected to change
among the group being studied.
They are defined concepts that can be observed or measured.
Researchers study how a change in one variable will influence another variable.
There are two main types of variables in quantitative research studies: the independent variable
and the dependent variable.
Researchers also need to pay attention to any potential confounding variables that could
influence the study.
This video will provide a brief definition of these variables as well as an example.
Research questions should clearly identify the variables under study.
In the above examples X symbolizes the independent variable and Y symbolizes the dependent variable.
In this video we are going to examine the question "Is there a difference in GPA between
nursing students who watch NurseKillam's videos and those who do not watch NurseKillam's videos?"
The variables under study in this question are GPA and watching NurseKillam's videos.
If this was a research question the study would outline a specific set of videos within
the methodology.
Watching the videos would be the independent variable.
The independent variable is the one that researchers think will have an effect on the dependent
variable or variables under study.
If the study is experimental the researcher will manipulate this variable.
This manipulation means that the researchers will cause the variable to happen in a group
of people.
For example, if we used our question for an experimental study the researcher would show
NurseKillam's videos to one group of students while ensuring that the other group of students
did not see them.
If the study is non-experimental the variable is assumed to happen naturally before or during
the study.
Instead of making some students watch the videos the researchers would measure or observe
if the videos were watched.
One way to do this would be to survey students to see if they had watched the videos.
Now that we know how the independent variable works, lets look at the dependent variable.
Like the name suggests, the dependent variable is assumed to be a result of or change based
on the presence, absence or magnitude of the independent variable.
One way to remember this relationship is that the outcome of the dependent variable depends
on the independent variable.
The question is worded in a way that identifies the variables to be studied.
From the wording of any question you should be able to identify the independent and dependent
variables under study.
Researchers want to explore, understand, explain or predict how the dependent variable will
respond to the independent variable.
The hypothesis will identify the researcher's best guess regarding the relationship between
these variables.
In our example the two variables are GPA and watching NurseKillam's videos.
It would not make sense for an increased GPA to cause students to watch the videos.
However, watching the videos may cause an increase a student's GPA.
Therefore, the dependent variable in our example is the GPA.
The one that is assumed to cause the change in the GPA is the independent variable.
Even though a higher GPA may be assumed to be a result of watching NurseKillam's videos
a causal relationship between the two variables cannot necessarily be proven.
Instead, a relationship can be identified but awareness of other factors needs to be
discussed.
When examining the relationship between the independent and dependent variables researchers
must also be aware of and control for as many confounding variables as possible.
Confounding variables include anything that may confuse or confound the relationship that
is being examined.
It is because of confounding variables that non-experimental research cannot prove cause
and effect relationships.
Researchers also need to be careful not to claim cause and effect relationships too easily
in experimental research because of these confounding variables.
In experimental research an attempt is made to control as many confounding variables as
possible.
In our example question, what things other than watching NurseKillam's videos may cause
an increased GPA?
Anything other than the independent variable that could have caused the student's GPA to
increase would be a confounding variable.
How about time spent studying, IQ, sleep patterns, life situations, stress levels, doing assigned
homework, class attendance among many other things.
It would be impossible to measure everything that could influence a student's GPA in one
study in order to prove that watching these videos actually caused the increased GPA.
Therefore, a relationship between the variables can be shown, but a cause and effect relationship
cannot be proven.
To remember what these types of variables are and how to identify them think about relationships.
The dependent variable is the one that depends on something and is expected to change.
Independent variables, like independent people do not rely on others.
Anything that may confuse this relationship is confounding.
For each of these questions try to identify the variables.
In the first question: "Does class attendance influence test scores?"
The study would be a descriptive non-experimental correlational study and the variables would
be class attendance and test scores.
Which variable is independent and which one is dependent?
Well, from the way it is worded you can tell that the researchers think that test scores
may be influenced by attendance.
So that means that the test scores would be the dependent variable.
Therefore, class attendance is the independent variable.
In the next question: "How are class attendance and test scores related to class schedules?"
the variables that are assumed to change include both class attendance and test scores.
Therefore, both of these variables are dependent.
There are a couple of messages I want you to take from this example: 1) Please note
that research questions may include many variables -- not just one independent and one dependent
variable.
2) whether a particular variable like class attendance is independent or dependent may
change depending on the role it plays in any given study.
Please pause this video and See if you can identify the type of variable in the rest
of the examples on your own and comment below.
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Thank you.