1. Research Methods With Statistics 8-10% of AP Exam
PSYCHOLOGY IS A SCIENCE!!!

2. Broad Categories of Research Methods
Descriptive
Correlational
Experimental

3. Comparing Research Methods
Basic Purpose
How conducted
What is manipulated
Descriptive
To observe and record behavior
Case studies, surveys, naturalistic observation
Nothing is “changed”
Examples?

4. Comparing Research Methods
Basic Purpose
How conducted
What is manipulated
Correlational
To detect naturally occurring relationships
(assess how well does one variable predict another)
Computing statistical associations
Nothing is manipulated
Examples?

5. Comparing Research Methods
Basic Purpose
How conducted
What is manipulated
Experimental
To explore cause and effect
Manipulate one or more factors (variables)
Use random assignment
Eliminate preexisting conditions
The independent variable(s)
Examples?

6. A Closer Look at Experiment Design

7. Experimental Design-only method meant to show “cause and effect”
Hypothesis-
A statement about the relation between two or more variables
Must be testable, verifiable and refutable
Null Hypothesis- a formal expression that there is NO relation between or among the variables under investigation
One attempts to reject the null when a relationship is observed

8. Experimental Variables
Independent-
variable manipulated by the experimenter (IV)
Dependent-
Measured variable influenced by the independent variable (DV)
Confounding- any variable besides the IV that could influence the experimental results (this is unwanted)

9. Subject Groups Experimental Group Control Group
The group that receives treatment (IV)
Control Group
Group that does not receive treatment (or receives treatment that is presumed to be ineffective e.g. placebo)
Used as a basis of comparison
Serves to eliminate alternative explanations of the results

10. Population Sample Representative
The larger group of people or animals from which the sample is drawn
Sample-set of subjects drawn from a particular population
Representative Sample- selected subjects are reflective of the population from which the sample is drawn
Sample
Representative

11. Control Measures Counterbalancing- Randomization-
Controls for order effect of conditions
Randomization-
Selection and assignment of subjects to groups through chance procedure

12. Control Measures Single-blind- Double-blind-
Controls subject awareness of group assignment
Double-blind-
Controls subject and experimenter awareness of group assignment

13. Operational Definition- an empirical measure of a vague term

14. Other Research Methods

15. Ex Post Facto Method- Latin for “after the fact”
Subjects selected based on conditions already present
Independent Variable (IV) established or manipulated by nature
Cannot make cause and effect statements about results
Most often used due to ethical concerns

16. Other Research Methods
Naturalistic Observations
Behavior observed or “watched” in a natural setting
Typically, behavior is not interfered with or altered

17. Other Research Methods
Case Studies
An intensive (often long-term) study of an individual or small group of individuals
In-depth information but may not always applicable to larger sample

18. Other Research Methods
Surveys
Methods used to measure attitudes, motives, opinions and such
Self report data: interpreted cautiously
Easily biased
Small rate of returns
Phrasing of questions may affect respondents’ answers

19. Other Research Methods
Correlational Method –
this is meant to show relationship among variables
Variables are quantified and statistically compared
Shows strength of relationship
Helps in study when experiment would be unethical (abuse, violence, unhealthy living styles)
Strength of relationship is shown by absolute value of correlation coefficient (more about this later)
Cheap/easy
However. . .

20. CORRELATION DOES NOT IMPLY CAUSATION!!!!
This is important to note. There is often an AP question regarding this concept.

21. READ ALL ABOUT IT SEE HANDOUT (last week)
ETHICS- ethical guidelines are established by the American Psychological Association (APA)
READ ALL ABOUT IT
SEE HANDOUT (last week)