1. science
2. mathematics
3. statistics

AP Psychology
Unit 2 Organizer
Research Methods (8-10%)
OBJECTIVES:
 differentiate types of research (e.g. experiments, correlational
studies, survey research, naturalistic observation, case studies)
with regard to purpose, strengths and weaknesses
 describe how research design drives the reasonable
conclusions that can be drawn (e.g. experiments are useful for
determining cause and effect; the use of experimental controls
reduces alternative explanations)
 identify independent, dependent, confounding, and control
variables in experimental designs
 distinguish between random assignment of participants to
conditions in experiments and random selection of
participants, primarily in correlational studies and surveys
 predict the validity of behavioral explanations based on the quality of research design (e.g.
confounding variables limit confidence in research conclusions)
 distinguish the purposes of descriptive statistics and inferential statistics
 apply basic descriptive statistical concepts, including interpreting and constructing graphs and
calculating simple descriptive statistics
 discuss the value of reliance on operational definitions and measurement in behavioral research
 identify how ethical and legal guidelines (e.g. those provided by the American Psychological
Association [APA], federal regulations, local institution review boards) protect research participants
and promote sound ethical principles
KEY TERMS/CONCEPTS:
 scientific method
 hypothesis
 replicate
 naturalistic observation
 observer effect
 participant observation
 laboratory observation
 case study
 survey
 representative sample
 population
 correlation
 correlation coefficient
 experiment
 operational definition
 independent variable
 dependent variable
 Hawthorne effect


















confounding variables
experimental group
control group
random assignment
placebo effect
experimenter effect
single-blind study
double-blind study
stereotype
sample
statistics
descriptive statistics
central tendency
measures of variability
frequency distribution
histogram
polygon
normal curve/bell curve

















skewed distribution
negatively skewed
positively skewed
bimodal distribution
measure of central
tendency
mean
outliers
median
mode
bimodal
range
standard deviation
inferential statistics
statistically significant
t-test
significant difference
ethics
Essential Understanding:
1. Observation is the most important aspect of psychological
research.
2. Operationalize means to define our variables in the manner
in which we are going to measure them.
3. Correlation measures the degree of the relationship
between variables and ranges from -1 to +1.
4. Correlation does not imply causation.
5. Independent variables are controlled by researchers, while
dependent variables are what researchers are measuring.
(Remember, dependent variable is dependent upon the
independent variable.)
6. Experimental, correlational, and descriptive methods all
have strengths and weaknesses in describing human
behavior.
7. Descriptive statistics describe the data gathered in research, while inferential statistics allows us to
draw conclusions about how this data can be generalized to a larger population.
8. Following ethical principles is vitally important in any kind of psychological research. (This has been
emphasized on recent AP exams.)
Comprehension Questions Chapter 1
As you read pages 20-51, stop and check your understanding of the material and apply your knowledge of
psychology to answer the following questions. You will answer these questions on a separate sheet of looseleaf. Please put a proper heading on your paper.
1. What are the steps in using the scientific method?
2. Describe how psychologists use case studies, naturalistic observation, and surveys to observe and
describe behavior. Identify advantages and disadvantages of each research method.
3. Why is random sampling important?
4. Describe positive and negative correlations.
5. Explain how correlational measures can aid the process of prediction but not provide enough evidence
of cause-effect relationships.
6. Describe the characteristics of experimentation that make it possible to isolate cause and effect.
7. Why, when testing a new drug to control blood pressure, would we learn more about its effectiveness
from giving it to half of the participants in a group of 1000 than to all 1000 participants?
8. Describe the three measures of central tendency, and what is the relative usefulness of the two
measures of variation?
9. How do we know whether an observed difference can be generalized to other populations?
10. Describe the ethical guidelines that safeguard human and animal research participants.