AP Psychology Methods and Statistics

1. Psychology
Unit 2: Methods and Statistics

2. Unit 2 Overview
• RMS 1.1: Describe the scientific method and its role in psychology
• RMS 1.2: Describe and compare a variety of quantitative and
qualitative research methods
• RMS 2.1: Identify ethical standards psychologist must address regarding
research with human participants.
Unit EQ:
How have philosophical perspectives and theoretical approaches
shaped the development of psychology?
You will need to be able to “Do” the following:

3. • Psychologists use several approaches to conducting
research, all sociologists follow a seven step research
process, and psychologists are bound by ethical guidelines.
You will need to be able to “Understand” the
following:

4. Unit 2 Outline
Concept 1: Conducting Psychological Research
Lesson: 1 2 3
Concept 2: Ethics

5. Conducting Psychological Research
Vocabulary
• scientific method
• Dependent variable
• Independent variable
• Experimental group
• Control group
• Double-blind study
• Confounding variable
• Placebo
EQ: How do psychologists use a variety of scientific research
methods to draw reasonable conclusions?
• RMS 1.1: Describe the scientific method and its role in
psychology
• RMS 1.2: Describe and compare a variety of quantitative
and qualitative research methods

6. Activator:
Steps of the Scientific Method

8. 1. Question
• Research questions are best
focused on behavior rather than
constructs that cannot be seen or
measured directly.
2. Hypothesis
• Form a hypothesis about the
answer to the research question.
• A hypothesis is an educated guess
• Specifies a relationship between
two aspects. (i.e. IV & DV)
3. Testing the Hypothesis
• A hypothesis cannot be considered
to be correct until it has been
scientifically tested and proved to
be right..
• May use a variety of research
methods to test a hypothesis.
4. Analyzing the Results
• What do their findings mean?
• Psychologists often look for
patterns and relationships in the
data.
5. Drawing Conclusions
• Psychologists draw conclusions about their research question and their
hypothesis.
• When observations do not support a hypothesis, they often must change the
theories or beliefs from which the hypothesis was derived.

9. • Psychologists use the experimental method to answer questions
about cause and effect.
• The hypothesis specifies the relationship between two aspects.
(i.e. the IV and DV)
• Independent Variables (IV) and Dependent Variables (DV)
• Experiments have variables, which are factors that can vary, or
change.
• The independent variable is the factor that researchers
manipulate.
• The dependent variable is the factor whose value depends on
a change made to the independent variable.
ResearchDesign:Hypothesisand Variables

10. Research Design: Operational Definition
• Specific statements describing how the IV is manipulated and
how the DV is measured.

11. Replication
• The ability of an entire experiment or study to be reproduced,
either by the researcher or by someone else working
independently.
• It is one of the main principles of the scientific method
• Why?

12. Adderall Experiment Exercise 1
Hypothesis: If a person diagnosed with Attention Deficit
Disorder (ADD) is given 20mg of Adderall then his/her focus
time will increase.
Assessment Prompt: Using all the hypothesis above, identify
the independent variable (IV) and dependent variable (DV).
Write your answer on a sheet of paper.
IVDV

13. Extraneous & Confounding Variables
Extraneous Variables: Undesirable variables that influence the
relationship between the variables that an experimenter is
examining.
Other Factors
(Extraneous &
Confounding
Variables)
Confounding Variables: Extraneous variables that vary with the
levels of the independent variable are the most dangerous type in
terms of challenging the validity of experimental results.

14. Variables
Questions:
1. In the Bystander Effect study or the Adderall Study, what
might be some of the confounding variables?
2. What does the phrase “the power of suggestion” mean?

15. Design an Experiment
• Assuming that the “power of suggestion” is the only variable
you are worried about, you are to design an experiment that
compensates for this variable.
• The details of your experiment should be written down.

16. Blind Studies
Double-Blind Studies
• Participants and researchers are unaware of who receives the treatment.
• Double-blind studies help researchers avoid the influence of expectations
and remain unbiased.
Single-Blind Studies
• Participants unaware of the treatment.
• Helps to avoid The Placebo Effect
– A placebo is a substance or treatment that has no effect apart from a
person’s belief in its effect.
– Feeling better simply because we expect to feel better—and for no
other reason—is an example of the placebo effect.

17. Groups
• Experimental and Control
Groups
– Members of an
experimental group
receive the treatment;
members of a control
group do not.
– All other conditions are
held constant for both
the experimental group
and the control group.
– A controlled experiment
uses both a control group
and an experiment
group.

18. Selection of Subjects
Random Sample
• The process of choosing
the research participants
from the population
• Happen BEFORE
assignment
Random
Assignment
• Each participant has
equal chance of being
placed into any group
• Placement into
experimental or control
group

19. Samples
• Sampling Bias (Selection Bias) is systematic error due to a non-
random sample of a population, causing some members of the
population to be less likely to be included than others, resulting in
a biased sample.
• Ensure samples accurately represent the population.
• Random Assignment & Sample
• individuals are selected by chance from the target population.
• Stratified Sample
• consists of subgroups in the population that are represented
proportionally.
• A large random sample is more likely to be accurately stratified
even if researchers take no steps to ensure that it is.

20. ParticipatoryLearning – FlawedExperiment
1. Hypothesis: “Smart” people tend to be more open-minded
and flexible.
2. Subjects: To test the hypothesis above, the experimenter
asks a wide variety of friends to complete a puzzle that
requires flexibility. Then he or she compares their scores.
3. Procedure: The experimenter tries to test the hypothesis
above on his friends, but they are too busy. Instead, he or
she uses strangers. The experimenter administers a brief
intelligence test, then gives subjects a test of flexibility. In the
morning he or she finds a group in the cafeteria and passes
out the tests to them. In the afternoon, the experimenter
finds people in the library who are studying by themselves.
Pick out the flaws in the following statement.

21. Extraneous Variables
• Placebo Effect
• Experimenter Effect (Bias)
• Observer Bias
• Sampling Bias/Selection Bias/Volunteer Bias
• Observer Effect (Hawthorne Effect)
• Courtesy Bias
Bias is a predisposition to a certain point of view

22. Quasi-Experiment (Natural
Experiments)
• Quasi (Similar or Seemingly)
• A quasi-experimental design is one that looks a bit like an
experimental design but lacks the key ingredient -- random
assignment.
• Experiments that take advantage of natural occurrences are
quasi-experiments
• Example 1: comparing achievement level of first-born children
with that of later-born children
• Example 2: comparing student performance at two schools, one
of which has a lower student-teacher ratio.
• The experimenter is unable to assign subjects to treatment
level - the subjects are already in pre-existing groups.

23. Adderall Experiment Exercise 2
Hypothesis: If a person diagnosed with Attention Deficit
Disorder (ADD) is given 20mg of Adderall then his/her focus
time will increase.
Assessment Prompt : Using all terms on the vocabulary sheet,
design and label and experiment that tests the above
hypothesis

24. Adderall Experiment Exercise 2
Vocabulary Application to the Experiment
Independent
Variable
Dependent
Variable
Control Group
Experimental
Group
Placebo
Single-Blind Study
Double-Blind Study
20mg of Adderall
Groups that receives the Placebo not the Adderall
Group that receives the Adderall
False pill to make up for the power of suggestion
Researcher knows who took the Adderall/Subject Doesn’t
Neither Researcher or Subject knows who took Adderall
Ability to Focus

25. • The tendency of research
subjects to change their
behavior as a result of their
awareness of being observed.
• It was named for a 1927
workplace study.
The Hawthorne Effect
Case Study: Learning from a Flawed Experiment
• Was not a blind study
• Did not have a control group
• Small Sample Size
• Results of the study may have
been misinterpreted
Flaws in the Hawthorne Study

26. Summarizing Activity
5 Steps of the Scientific Method, 2 Variables,
and Questions Remaining

27. ConductingPsychologicalResearch:MethodsandData
Vocabulary
• Quantitative
• Qualitative
• Naturalistic Observation
• Interviews
• Case Study
• Psychological Tests
• Longitudinal method
• Cross-Sectional Method
• Survey Method
EQ: How do psychologists use a variety of scientific
research methods to draw reasonable conclusions?
Activator: Remember the Methods of Research

28. Bystander
Effect
And
Diffusion of
Responsibility
Kitty
Genovese

29. Assignment: Experiment Creation
• Create a testable thesis
• Your group should then design an experiment that could be
used to test the phenomenon of diffusion of responsibility
(bystander effect).
• Include as many details as possible.
• Be prepared to share out.

30. Psychological Methods

31. Psychological Methods

32. Psychological Methods

33. Volunteer Bias
• When conducting surveys, bias may occur on the part of the
respondents.
• Volunteer bias: People who volunteer to participate in studies
may have a different outlook from people who do not volunteer.
– Volunteers are usually more willing to disclose personal
information.
– They may have more spare time to participate.
– Volunteers probably do not represent the target population.

34. ConductingPsychologicalResearch:MethodsandData
Vocabulary
• Median
• Mode
• Mean
• Correlation coefficient
• Central tendency
• variability
• histogram
• descriptive statistics
• Inferential statistics
• range
• standard deviation (SD)
• Statistical significance
• normal distribution
• sample
Activator:
EQ: How do statistical concepts apply to psychological
research?
How do ethical and legal guidelines impact psychological
research?

35. Statistics
• Statistics: Branch of mathematics concerned with the
collection and interpretation of data from a sample.
• Descriptive Statistics: a way of organizing numbers and
summarizing them so that they can be understood.
• Two Main Types
• Measure of Central Tendency: Used to summarize the data
and give you one score that seems typical
• Measure of Variability: Used to indicate how spread out the
data are.
• Inferential Statistics: drawing conclusion by analyzing the data
to find differences and meaning in the data

36. Critical Thinking Activity
Experimental
Group
Control
Group
Average Score
(Mean)
81% 67%
Highest Score 89% 87%
Lowest Score 73% 34%
Median Score
(Mid-Point)
79% 77%
Complete Methods of Psychology: Critical
Thinking Activity worksheet in your packet.

37. Descriptive Statistics

38. Central Tendency
• Mean: “The Average” Most commonly used measure of
central tendency. Add up all the numbers in a set and then
divide by the total amount of numbers used.
• Median: Middle number in a set of data(Helps if there are a
few extreme scores)
• Mode: Most frequent score
• Bimodal: two very different yet very frequent scores. In this
case no measure of central tendency does you much good.

39. Frequency Distribution
Frequency Distribution: A table or graph that shows how often
different numbers, or scores, appear in a particular set of scores.
Polygon Histogram (bar graph) Frequency Table

40. Measures of Variability
• Range: Difference between the highest and lowest score in a
set of scores.
• Is limited as a measure of variability when extreme scores are
involved

41. Measures of Variability
• Standard Deviation:

42. Measures of Variability
• Z-score: The way of calculating how many standard deviations
you are away from the mean. Provides a way of comparing
sets of data to the normal distribution (such as IQ test scores)

43. Standard Deviation: IQ

44. Curve

45. Inferential Statistics

46. One method psychologists use to analyze and interpret their
observations is correlation. Correlation is a measure of how closely
one thing is related to another. The stronger the correlation between
two things, the more closely the two things are related.
• Positive correlation occurs
when an increase in one thing
is accompanied by an increase
in the other.
• Negative correlation occurs
when a increase in one thing is
accompanied by a decrease in
the other. (or vice versa)
Positive and Negative
Correlation
Analyzing the Observations
• Correlation describes
relationships, but it does not
reveal cause and effect.
• Just because two things are
related does not necessarily
mean that one causes the other.
Limits of Correlation

47. Correlation: Scatterplot

48. Correlation vs. Causation
• What do you think is meant by the statement , “Correlation
does not imply causation.”?

49. Correlational Coefficient
• It represents the direction and strength of the relationshp.
• Ranges between +1.0 and -1.0.
• The closer r is to +1.0 and -1.0 the stronger the relationship

50. Assignment: Frankenstein and Ethics
• In your packet, read Ethics in
Experimentation: Frankenstein and
Complete Questions 1, 3-5
• REMINDER: UNIT 1 Exam is Wednesday
STUDY!!!

51. APA Ethical Guidelines
for Human Research
• Informed Consent - participants must know that they are involved in
research and give their consent or permission
• Deception - if the participants are deceived in any way about the nature of
the study, the deception must not be so extreme as to invalidate the
informed consent.
• Coercion - participants cannot be coerced in any way to give consent to be
in the study.
• Anonymity-the identities and actions of participants must not be revealed
in any way by the researcher.
• Risk-participants cannot be placed at significant mental or physical risk.
This clause requires interpretation by the review board.
• Debriefing Procedures -participants must be told of the purpose of the
study and provided with ways to contact the researchers about the results.

52. Unit 1 Exam Topics
• Definition of Psychology
• Applied vs. Research Psychologist
• Historical Figures/Contributions
• Psychological Perspectives
• Experimentation (Terms and Application)
• Data (Correlation)
• Methods of Research
• Ethics