1. Chapter 2: The Research Enterprise in Psychology

2. Why do Psychology?
Hindsight Bias: tendency to believe, after learning an outcome, that one would have foreseen it
Overconfidence: we tend to think we know more than we do

3. The Scientific Approach: A Search for Laws
Basic assumption: events are governed by some lawful order
Goals:
Measurement and description
Understanding and prediction
Application and control

4. Flowchart of steps in a scientific investigation

5. The Scientific Method
Theory: an explanation using an integrated set of principles that organizes & predicts observations
Hypothesis: a testable prediction, often implied by a theory.
If __(IV)___ then ___(DV)____.

6. The Scientific Method: Terminology
Operational definitions: are used to clarify precisely what is meant by each variable
Population: who are you gathering your samples from?
Random Sample: out of the population everyone has an equal chance of being selected
Sample: the group of subjects selected for the study
-Participants/Subjects are the organisms whose behavior is systematically observed in a study

7. The relationship between the population & the sample

8. 1) Experimental Research: Looking for Causes
Experiment = manipulation of one variable under controlled conditions so that resulting changes in another variable can be observed
Detection of cause-and-effect relationships
Independent variable (IV) = variable manipulated
Dependent variable (DV) = variable affected by manipulation or being measured
How does X affect Y?
X = Independent Variable
Y = Dependent Variable

9. Experimental & Control Groups:
Random Assignment every person has the same chance of being assigned to either group
1) Experimental group the group that receives the change (IV)
2) Control group remains the same, baseline (DV)
Resulting differences in the two groups must be due to the independent variable
Extraneous variables things you cannot control (outside)
Confounding variables any possible variable other than IV that may cause the observed effect
(you cannot separate within)

10. The Basic Elements of an Experiment

11. Experimental Designs: Variations
Expose a single group to two different conditions
Reduces extraneous variables
Manipulate more than one independent variable
Allows for study of interactions between variables
Use more than one dependent variable
Obtains a more complete picture of effect of the independent variable

12. Manipulation of two IV in an experiment

13. Strengths & Weaknesses of Experimental Research
conclusions about cause-and-effect can be drawn
Weaknesses:
artificial nature of experiments
ethical and practical issues

14. 2) Correlational Methods: Looking for Relationships
Methods used when a researcher cannot manipulate the variables under study
Naturalistic observation
Case studies
Surveys
Allow researchers to describe patterns of behavior & discover links or associations between variables but cannot imply causation

15. Comparison of Major Research Methods

16. Key Data Collection Techniques

17. The Scientific Method:
Findings are shared through reports in scientific journals – periodicals that publish technical and scholarly material
Advantages of the scientific method: clarity of communication and relative intolerance of error

18. Statistics & Research: Drawing Conclusions
Statistics – using mathematics to organize, summarize, and interpret numerical data
1) Descriptive statistics: organizing and summarizing data
2) Inferential statistics: interpreting data and drawing conclusions

19. 1) Descriptive Statistics: Measures of Central Tendency
Measures of central tendency = typical or average score in a distribution
Mean: arithmetic average of scores
Median: score falling in the exact center
Mode: most frequently occurring score

20. Measures of central tendency

21. Descriptive Statistics: Variability
Variability = how the data are dispersed or spread around the mean
Range = the distance btw the highest & lowest scores
Standard deviation (SD) = the average distance of a scores from the mean
High variability in data set = high standard deviation
Low variability in data set = low standard deviation

22. Variability & the Standard Deviation

23. 1) Descriptive Statistics: Frequency Distribution
Frequency Distribution: an arrangement of data points based on how frequently they occur
Normal Distribution: a frequency distribution w/ a symmetrical be;;-shaped curve

24. Normal Distribution & SD24

25. Descriptive Statistics: Correlation
When two variables are related to each other, they are (co)rrelated
Correlation Coefficient = numerical index representing the relationship between 2 things <--> -1
Positive Correlation as one increases the other variable increase (same way)
Negative Correlation as one variable goes up the other goes down (opposite ways)
Numbers closer to 1 (+ or -) indicate stronger relationship 25

26. Interpreting Correlation Coefficients

27. 2) Inferential Statistics: Interpreting Data & Drawing Conclusions
Hypothesis testing: do observed findings support the hypotheses? Are findings real or due to chance?
Statistical significance when the probability that the observed findings are not due to chance
The closer the Correlation Coefficient is to -1 or +1 the variables are causation (-.5 -> -1 /or/ +.5-> +1)
Two Types of Errors occur in significance testing:
1) Type 1 Error: False negative; fails to perceive an effect that is there
2) Type 2 Error: False positive; perceives an effect that is not there

28. Correlation: Prediction (Not Causation)
Higher correlation coefficients = increased ability to predict one variable based on the other
SAT/ACT scores moderately correlated with first year college GPA
2 variables may be highly correlated, but not causally related
Foot size and vocabulary positively correlated
Do larger feet cause larger vocabularies?

29. Methodological Pitfalls
Sampling bias excluding a group of the population
Placebo effects the belief that a medicine cured your illness (sugar pill)
Distortions in self-report data:
Social desirability bias answer in a desirable response, no the truth.
Response set tendency to respond the same way
Experimenter bias expectations or preferences about the outcome of a study influence the results obtained.
Double-blind solution either the researcher nor participant know which group they are in

30. Ethics in Psychological Research: Do the Ends Justify the Means?
The question of deception
The question of animal research
Controversy among psychologists and the public
Ethical standards for research: the American Psychological Association (APA)
Ensures both human and animal subjects are treated with dignity

31. Ethics in Research