What Is A Experimental Variable

What are Independent and Dependent Variables?

By Dr. Saul McLeod, updated 2019

Variables are given a special name that merely applies to experimental investigations. Ane is chosen the dependent variable and the other the independent variable.

The independent variable is the variable the experimenter manipulates or changes, and is assumed to take a direct effect on the dependent variable. For example, allocating participants to either drug or placebo conditions (independent variable) in order to measure any changes in the intensity of their feet (dependent variable).

In a well-designed experimental report, the contained variable is the only of import departure between the experimental (east.g. treatment) and control (eastward.one thousand. placebo) groups.

The dependent variable is the variable existence tested and measured in an experiment, and is 'dependent' on the independent variable. An example of a dependent variable is depression symptoms, which depends on the contained variable (type of therapy).

In an experiment, the researcher is looking for the possible consequence on the dependent variable that might be caused past irresolute the independent variable.

Examples of Contained and Dependent Variables in Experiments

For instance, we might change the type of information (e.g. organized or random) given to participants to see what effect this might have on the amount of information remembered.

In this particular example the type of data is the contained variable (because it changes) and the amount of information remembered is the dependent variable (because this is being measured).

Activity

For the following hypotheses proper name the IV and the DV.

1. Lack of sleep significantly affects learning in 10-year-quondam boys.IV............................................................
DV...........................................................
2. Social class has a significant event on IQ scores.
IV............................................................

DV.......................................................…

3. Stressful experiences significantly increment the likelihood of headaches.

IV............................................................

DV...........................................................

4. Fourth dimension of solar day has a significant result on alacrity.

IV............................................................

DV...........................................................

Operationalizing Variables

To ensure crusade and effect is established it is important that we place exactly how the independent and dependent variables will be measured, this is known every bit operationalising the variables.

Operational variables (or operationalizing definitions) refer to how you will ascertain and measure out a specific variable every bit it is used in your study. This enables another psychologist to replicate your research and is essential in establishing reliability (achieving consistency in the results).

For example, if we are concerned with the effect of media violence on assailment, then we need to be very clear what we mean by the different terms. In this example, we must state what we hateful past the terms "media violence" and "assailment" equally nosotros will study them.

Therefore, you could state that "media violence" is operationally divers (in your experiment) every bit 'exposure to a 15 minute film showing scenes of physical assault'; "assailment" is operationally defined as 'levels of electrical shocks administered to a 2nd 'participant' in another room'.

In another example, the hypothesis "Immature participants will have significantly meliorate memories than older participants" is non operationalized. How practice we define "young", "erstwhile" or "retention"? "Participants aged between xvi - thirty will recall significantly more than nouns from a listing if twenty than participants aged betwixt 55 - 70" is operationalized.

The key betoken here is that nosotros have made it absolutely clear what we mean past the terms as they were studied and measured in our experiment. If we didn't do this and then it would exist very hard (if non impossible) to compare the findings of different studies into the same behavior.

Operationalization has the great advantage that it generally provides a clear and objective definition of even complex variables. It also makes information technology easier for other researchers to replicate a study and check for reliability.

Activity

For the following hypotheses proper name the 4 and the DV and operationalise both variables.

1. Women are more than attracted to men without earrings than men with earrings.
I.V._____________________________________________________________
D.5. ____________________________________________________________

Operational definitions:

I.V. ____________________________________________________________

D.V. ____________________________________________________________

two. People learn more when they study in a quiet versus noisy place.

I.V. _________________________________________________________

D.V. ___________________________________________________________

Operational definitions:

I.V. ____________________________________________________________

D.V. ____________________________________________________________

three. People who exercise regularly sleep better at night.
I.V._____________________________________________________________
D.V. ____________________________________________________________

Operational definitions:

I.V. ____________________________________________________________

D.V. ____________________________________________________________

How to reference this article:

McLeod, S. A. (2019, August 01). What are independent and dependent variables. Simply Psychology. www.simplypsychology.org/variables.html

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