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Variables
O Variable (defined)
“Any concept that can have two or more
values.”
O Variables can be described in two important
ways
O How variables are measured
O How variables function
Describing Variables
How Variables are Measured
O Nominal
O Dichotomous (only two categories)
O Polytomous (more than two
categories)
O Continuous
Describing Variables
Now it’s your turn
O Get in groups of 4 or 5
O Come up with three examples of
each different type of variable:
A. Dichotomous
B. Polytomous
C. Continuous
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Function of Variables
How Variables Function
O Independent variable
O Dependent variable
O Mediating variable
O Moderating variable
Function of Variables
Independent vs. Dependent Variables
O Independent Variable: A variable that is
thought to influence changes in another variable.
X
Smoking
Studying
Y
causes
influences
cancer.
the grade you
get in a class.
crankiness.
Lack of sleep leads to
O Dependent Variable: A variable that is thought
to be changed by another variable.
Mediating Variable
O A variable that intervenes between an
independent and dependent variable to explain
the relationship between the two variables.
W
Smoking
X
Y
causes you to smell
which leads to
having
fewer friends.
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Function of Variables
Moderating Variable
O A variable that modifies the relationship
between other variables.
Modifies = changes (increases or decreases)
Difference between moderating and mediating
variables:
Mediating variable explains the relationship
between the 2 other variables.
Moderating variable influences the strength
of a relationship between the other two
variables.
Function of Variables
Example
O Variable 1: Social class (SES)
Meditating variable: Education
Moderating variable: Age
O Variable 2: Frequency of breast self-
exams (BSE)
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