1. Psychological Research
Methods: purpose, strengths, and weaknesses

2. Goals of Psychology
DESCRIPTIVE (surveys, case studies, naturalistic observations)
PREDICTIVE (correlations)
EXPLANATORY (experimentation)

3. Naturalistic Observations
Beware of the Hawthorne Effect

4. Case Studies
Very detailed information about one or few subjects giving interesting insight
Inability to replicate
Time consuming

5. Surveys Strengths Weaknesses Cheap and fast Low response rate
Large sample size
What people say they do isn’t always what they actually do
Can be correlational
Wording Effects

6. Correlational Research
Shows a relationship between 2 variables
Correlation does NOT show causation

7. Positive or Negative Correlation
Variables that are directly related move up together and down together
Variables that are inversely related move in opposite directions

8. Positive or Negative?
Studying and Grades
Drug use and Grades

9. Correlation Coefficient
Tells us the strength and the direction of the relationship
Strong relationships are ones that approximate 1.00
Stronger relationships allow for greater predictive power
Positive correlations are noted with a “+” symbol
Negative correlations are noted with a “-” symbol
-.80 and represent equally strong relationships
-.83 is a much stronger relationship than +.65
Which is a stronger correlation?
-.13 or +.38
-.72 or +.59
-.91 or +.04

10. Experimentation
Purpose: Isolate the effects of one or more variables by
Experiments are useful for determining cause and effect
The ONLY method that shows causation
The use of experimental controls reduces alternative explanations

11. Components of an Experiment
Sample
Random sample
Random stratified sample
Random Assignment
Control Group & Experimental Group
Independent Variable & Dependent Variable

12. Traps in Research Extraneous Variables Confounding Variables
Quasi-experiment
Within-Subjects Design
Between-Subject Design
Placebo Effect
Single-blind study
Experimenter Bias
Double-blind study