Transcript Research in Psychology

Research in Psychology
Chapter Two
8-10% of Exam
AP Psychology
Theories

tentative explanations that must be
subjected to scientific evaluation
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constantly being formulated, evaluated,
reformulated, and sometimes abandoned
based on research results
Goals of Psychological Research

describe phenomenon

make predictions

demonstrate some control over variables

explain the phenomenon with confidence
Naturalistic Observation
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Feature: The process
of watching without
interfering as
behavior occurs in the
natural environment
Strengths: Provides
descriptive data about
behavior presumably
uncontaminated by
outside influences
Pitfalls: Observer bias
and participant selfconsciousness can
distort results
Case Studies
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Feature: Intensive examination of the behavior and
mental processes associated with a specific person,
group or situation.
Strengths: Provide detailed descriptive analysis of new,
complex, or rare phenomenon.
Pitfalls: May not provide representative picture of
phenomena.
Surveys
Feature: Standard set of
questions asked of a large
number of participants –
asks people about their
behavior, attitudes,
beliefs, and opinions
 Strengths: Gather large
amounts of descriptive
data relatively quickly
and inexpensively.
 Pitfalls: Sampling errors,
poorly phrased questions,
and response biases can
distort results.
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Correlational Studies
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Feature: Examine relationships between research
variables.
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Strengths: Can test predictions, evaluate theories,
and suggest new hypotheses.
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Pitfalls: Cannot infer causal relationships between
variables.
Correlation
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Correlation – the degree to which one
variable is related to another
Correlation Coefficients

Correlation Coefficient – a statistic, r, that
summarizes the strength and direction of a
relationship between two variables
Indicates direction
of relationship
(positive or negative)
Correlation
coefficient
r = +.37
Indicates strength
of relationship
(0.00 to 1.00)
Experiments
Feature: Manipulation of an independent
variable and measurement of its effects on a
dependent variable.
 Strengths: Can establish a cause-effect
relationship between independent and
dependent variables.
 Pitfalls: Confounding variables may prevent
valid conclusions.
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Key Terms in experiments—
KNOW THEM!!!
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Hypothesis
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Confounding Variables
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Independent Variable
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Random Variables
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Dependent Variable
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Participant Expectations
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Operational Definition
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Placebo
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Experimental Group
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Confirmation Bias
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Control Group
Figure 2.1: A Simple Two-Group
Experiment
Independent Variable: Whether or not one
received the EMDR treatment.
Dependent Variable: Anxiety level.
Sources for Confounding
Variables
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Random Variables
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Participants’ Expectations
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Importance of random
assignment
Placebo effect
Experimenter Bias
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Can be minimized through the
use of a
double-blind design
Selecting Human Participants for
Research
Sampling = the process
of selecting participants
for research
 The sampling procedures
used can:

 Affect
the research
results.
 Limit the meaning of the
results
Representative Samples
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A group of research participants whose
characteristics fairly reflect the characteristics of
the population from which they were selected
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If psychologists want to make scientific statements about
the behavior and mental processes of any large group, they
must use a representative sample of participants
Random vs. Biased Samples
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Random - A group of
research participants
selected from a
population whose
members all had an
equal chance of being
chosen
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Biased – A group of
research participants
selected who did not
have an equal chance of
being chosen
Convenience Samples
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Populations that are conveniently available
to the researcher
 Researcher
must check age, gender,
ethnicity, and other characteristics of
participants
Statistical Analysis of
Research Results
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Descriptive Statistics - #s
that DESCRIBE a set of
research data
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Measures of Central
Tendency
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Measures of Variability
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Correlation Coefficients
Inferential Statistics – a set
of mathematical procedures
that help researchers INFER
what their data mean
Measures of Central Tendency
for Descriptive Statistics
 Mean
– average
 Median –
halfway point
 Mode – occurs
most frequently
Measures of Variability
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Range – difference between highest and
lowest values
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Standard Deviation (SD) – average distance
between each score and the mean of the
data set
Table 2.4: A Set of Pretreatment Anxiety
Ratings