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CONCEPTS
          Independent Variable and Dependent Variable

   What is an independent variable?   What is a dependent variable?
It is important to compare independent vs. dependent variables.  The
independent variable and dependent varaible are two different types
of variables in an
experiment.

Independent Variable Definition
  
    What is an independent variable?  The independent variable is
the variable that is
manipulated by the researcher.  The independent
variable is something that is hypothesized to influence the
dependent variable.  The researcher determines for the participant
what level or condition of the independent variable that the
participant in the experiment receives.  For example, each
participant in the experiment may be randomly assigned to either an
experimental condition or the control condition.

Dependent Variable Definition

   What is a dependent variable?  The dependent variable is the
variable that is simply
measured by the researcher.  It is the variable
that reflects the influence of the independent variable.  For example,
the dependent variable would be the variable that is influenced by
being randomly assigned to either an experimental condition or a
control condition.   

Examples of Independent Variable and Examples of Dependent
Variable

    
In order to clarify the concepts of independent variable and
dependent variable, it is important to provide examples.
    Imagine that you wished to know whether listening to music
would increase productivity in the workplace.  You randomly assign
each participant in this experiment to either an experimental
condition or a control condition.  In the experimental condition,
participants listen to music while they work.  In the control
condition, the participants do not listen to music while they work.  
In this example, listening to music vs. not listening to music is the
independent variable.  The dependent variable in this example is
productivity.
   Now imagine you wish to know whether a one-page or two-page
resume is more persuasive.  You randomly assign each participant to
read a one-page or two-page resume, and then they make a
judgment about whether the person should be hired for a job.  In this
example, the independent variable is the one-page vs. two-page
resume.  The dependent variable in this example is the hiring
judgment.