1. Research in Psychology Chapter Two 8-10% of Exam
Crash Course
AP Psychology

2. Theories
tentative explanations that must be subjected to scientific evaluation
constantly being formulated, evaluated, reformulated, and sometimes abandoned based on research results

3. Goals of Psychological Research
describe phenomenon
make predictions
demonstrate some control over variables
explain the phenomenon with confidence

4. Naturalistic Observation
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 self- consciousness can distort results

5. Case Studies
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: Limited sample = may not provide representative picture of phenomena.

6. 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.

7. Correlational Studies
Feature: Examine relationships between research variables.
Strengths: Can test predictions, evaluate theories, and suggest new hypotheses.
Pitfalls: Cannot infer causal relationships between variables.
Reminder!: Correlation does NOT prove cause!

8. Correlation
Correlation – the degree to which one variable is related to another
r = correlation
+1 = perfect positive
-1 = perfect negative

9. Correlation Examples:

10. Experiments: SNL Sketch
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.

11. Figure 2.1: A Simple Two-Group Experiment
Independent Variable: Whether or not one received the EMDR treatment.
Dependent Variable: Anxiety level.

12. Sources for Confounding Variables
Random Variables
Importance of random assignment
Participants’ Expectations
Placebo effect = use single- blind
Experimenter Bias
Can be minimized through the use of a double-blind design

13. 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

14. Representative Samples
A group of research participants whose characteristics fairly reflect the characteristics of the population from which they were selected
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

15. Random vs. Biased Samples
Random - A group of research participants selected from a population whose members all had an equal chance of being chosen
Biased – A group of research participants selected who did not have an equal chance of being chosen

16. Convenience Samples
Populations that are conveniently available to the researcher
Researcher must check age, gender, ethnicity, and other characteristics of participants

17. Statistical Analysis of Research Results
Descriptive Statistics - #s that DESCRIBE a set of research data
Measures of Central Tendency
Measures of Variability
Correlation Coefficients
Inferential Statistics – a set of mathematical procedures that help researchers INFER what their data mean

18. Measures of Central Tendency for Descriptive Statistics
Mean – average
Median – halfway point
Mode – occurs most frequently

19. Measures of Variability
Range – difference between highest and lowest values
Standard Deviation (SD) – average distance between each score and the mean of the data set

20. Videos to watch for review
Crash Course
Correlation Coefficient
Standard Deviation

21. Sample Question for Measures of Central Tendency
Put the numbers in order
2, 3, 3, 5, 5, 7, 10, 10
5 is the median (middle)
This question could easily also ask about mean and mode

22. Sample Measures of Variability
Because you’re being asked to look at correlation, you would use a scatterplot = # 31 = D
Because you’re looking for correlation, you would have to narrow #32 down to letter D or E because r = the correlation coefficient
After you chart this on a scatterplot it will have a downward sloping plot line
Upward slope = positive correlation
Downward slope = negative correlation
D is the best answer because r = -.90 is negative correlation (-1 = perfect negative correlation)
NOTE: You would use a histogram (bar graph) if being asked to summarize, compare, or communicate results

23. Complete M & M’s Activity

24. Duez Video Lecture on Statistics
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