Transcript A.P. Psychology 2 (B) - Non-Experimental Research Designs

Unit 2 (B):
Non-Experimental
Research Designs
Mr. McCormick
A.P. Psychology
Do-Now
(In Journal)

Think of a psychological phenomenon that you
would be interested to research (a behavior, habit,
disorder, etc.)
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Briefly describe how you could hypothetically carry out
your research
Pre-Research Decisions
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Population:
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All the cases in a group being studied, from which samples
may be drawn
E.g. The entire CHS student body (2,000 students)
Sample:
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Small group of participants, out of a total population, that a
researcher studies
Representative vs. Non-representative
E.g. 200 CHS students
Pre-Research Decisions
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What might a representative sample of
CHS students look like?
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How could we effectively get a
representative sample of CHS students?
Pre-Research Decisions
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Random Sample:
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A sample that fairly represents a population because each
member has an equal chance of inclusion
Non-Experimental
Research Designs
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Naturalistic Observation:

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Case Study:
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Observation of subject(s) in a natural setting without
manipulating or controlling the situation (e.g. watching
teenagers in a mall)
Intensive investigation of participant(s) (e.g. long-term
interviews, living with participants, journals, video blogs)
Survey:
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Information is obtained by asking many individuals a fixed
set of questions (e.g. questionnaire on self-reported attitudes
or behaviors)
Non-Experimental
Research Designs
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Longitudinal Study:
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Studying a group of participants over a number of years (e.g.
following a group of high school freshmen throughout their
high school career)
Cross-Sectional Study:
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Studying groups of participants of different ages and
comparing them to draw conclusions about age (e.g. studying
a group of freshmen and seniors)
Non-Experimental
Research Designs

Think of an example in which each of the
following research designs would be most
effective:
Naturalistic Observation
 Case Study
 Survey
 Longitudinal Study
 Cross-Sectional Study

Correlation
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Correlation:
A measure of the extent to which two factors vary
together (and how well one factor predicts the other)
 Does not demonstrate causation
 Can be positive or negative
 Can be illusory (appears to be relationship where
none exists)
 Measured with scatterplots
 Measured by a correlation coefficient “r” (-1 to +1)
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Correlation
What naturally-existing
correlations
can you think of?
Correlation
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Positive Correlation:
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Direct relationship
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Both factors increase
together; Both factors
decrease together
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E.g. Amount of sleep and
GPA
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Right: Perfect Positive
Correlation (r=+1.00)
Height and Temperament in Men
r=+0.63
Correlation
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Negative Correlation:
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Inverse relationship
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One factor increases, while
the other decreases
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E.g. Physical exercise and
fat content
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Right: Perfect Negative
Correlation (r=-1.00)
Correlation

What do you think a scatterplot
would look like for two factors
that are not correlated?
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What would its correlation
coefficient be?
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r=0.00
Correlation ≠ Causation
Review

What is the difference between a population and a
sample?
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How could one effectively create a representative
sample?

What is the difference between a positive and
negative correlation?
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What are some implications of a correlation?
Homework
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Research Study Response #40: “Obey At Any
Cost?” (Pgs. 308-317)