1. Psychological Research Methods and Statistics
Chapter 2

2. 2.1 What is Research?
SAMPLE- the small group of participants, out of the total number available, that a researcher studies. - representative - nonrepresentative - random sample - stratified sample
A sample must be representative of the population a researcher is studying. For example, if you want to know how tall American men were, you don’t want to include a disproportionately large number of professional basketball players. Such a sample would be nonrepresentative.
How to avoid: Take a purely random sample, so that each individual has an equal chance of being represented. For example, every twentieth name on a school enrollment list. OR you can deliberately pick individuals who represent the various subgroups in the population being studied. For example, the psychologist doing research on school children might select students of both sexes, of varying ages, of all social classes, and from all neighborhoods.

3. Methods of Research Survey
Asking many people a fixed set of questions about a particular subject
Advantages: They quickly and efficiently collect vast amounts of data from a large sample of diverse people.
Disadvantages:
1.) Wording of Question is Key Why?
2.) Who asks them is influential Why?
Radio-talk shows host that surveys his listeners about a political issue,
The results are not likely to generalize the people as a whole.
Those who feel strongly enough to volunteer their opinions may differ from .
People lie to impress the surveyer. Are Americans ready and willing to vote for an African American President?
How many times have you drank alcohol? Rather than Have you ever drank alcohol?
1936 presidential election the Literary Digest mailed 10 million ballots as a poll. With 23% responding the Literary Digest predicted Landon would win comfortably. FDR won with 61% of the vote. The digest sampled owners of telephones and cars and members of clubs. Over-sampling of the wealthy.

4. Surveys
Types of Techniques
Interview
Questionnaire

5. Methods of Study (cont)
B. Case Study
An in-depth analysis of thoughts, feelings, beliefs, behaviors, etc. of a single individual or group.
Freud used case studies of his patients in developing his theories on personality.
Advantages:
Depth allows for cause and effect to be determined
Disadvantages:
Generalizations cannot be made- one person only kind of data. By itself, a case study does not prove or disprove anything. It may lead to ideas on experiments to make.

6. Case Studies: Techniques
Types of Techniques
Interview
Questionnaire
Standardized Tests
Lab experiments (lab setting)---controlled
Naturalistic setting---observe only
Diaries. By itself however, a case study does not prove or disprove anything. The results cannot be generalized to anyone else. Case studies, though, provide a wealth of descriptive material that may generate new hypothesis that researchers can then test under controlled conditions with comparison groups.

7. Methods of Study (cont)
C. Naturalistic Observation: The Psychologist observes the subject in a natural setting without interfering.
Chimps hunt and eat larger animals and make and use tools more than any other species except humans. Godall also witnessed the first known instance in which one group of chimps systematically killed another group, even though the first group’s survival was not threatened. The discovery surprised naturalists and suggested that behaviors like hunting, using tools, and warfare are not uniquely human.
What might be a criticism of Jane Goodall’s Naturalistic Observation?
The interaction with the animals. She named them instead of numbered them. This promotes feelings for the animals and instead you want to remain an innocent bystandered.
Researchers need to know how people and animals behave naturally, when they are not conscious of being observed during an experiment. The cardinal rule of naturalistic observation is avoid disturbing the people or animals you are studying by concealing yourself or by acting as unobtrusive as possible. Otherwise you may observe a performance produced because of the researcher’s presence. Hawthorne effect. –A group of industrial psychologists set out to determine worker’s productivity at a GE plant. At first they gradually increased the lighting in the room productivity went up. Participants were then permitted to take breaks. Productivity went up. Next they reduced level of lighting, yet again productivity went up. No matter what they did productivity went up.Why? Realized being watched and receiving special attention.
Jane Goodall

8. Methods of Study (cont)
D. Longitudinal Studies: data is collected about a group of participants over a number of years to assess how certain characteristics change or remain the same during development.
Problems? Very time consuming.
They are an ideal way to examine consistencies and inconsistencies in behavior over time.

9. Methods of Study (cont)
Cross-Sectional Study:
Data are collected from groups of participants of different ages and compared so that conclusions can be drawn about differences due to age.
Advantages: Compared to longitudinal studies? Less expensive than longitudinal studies and reduce the amount of time necessary for the studies. Age differences main.
3, 4 ,6 7, year ols they showed them pictures of a series looking lady and asked what they thought the woman was thinking about. The psychologists found that the older children had a clearer picture of mental processes.

10. Methods of Study (cont)
F. Experiment
A method for identifying cause and effect relationships by following a set of rules that minimize the possibility of error, bias or chance
Experimentation enables the investigator to control the situation and to decrease the possibility that unnoticed, outside variables will influence the results.
Experimentation enables the investigation to control the situation and to decrease the possibility that unnoticed, outside variables will influence the result.

11. Correlation An association or relationship between two or more events
Correlation coefficient: a number that indicates the strength of a relationship between two events

12. Correlation Coefficients
Perfect Positive (+1.00): an increase in one event is always matched by an increase in the 2nd event
Positive (+0.01 to ): as one event increases, the 2nd event tends to, but not always, increase
The amount of time I spend studying Psychology and the grade I earn in class.
Hyperactivity has a genetic basis. Perfect Positive correlation: if one identical twin has hyperactivity, then the other twin always has hyperactivity. A correlation of +1 is virtually never found in applied psychological research.

13. Correlation Coefficients
Negative (-0.01 to –0.99): as one event increases, the 2nd event tends to, but does not always, decrease
Perfect Negative (-1.00): as one event increases, the 2nd event always decreases equally
The number of hours I spend practicing my tennis serve and the number of double faults you serve.

14. Correlation vs. Causation
Correlation does NOT show causation
-Children that watch a lot of violent TV and aggressiveness.

15. Scientific Method: 6 Rules of Conducting Experiments
Ask Research Question
Form a Hypothesis
Determine Variables
Independent variable (controlled)
Dependent variable (affected)
Independent variable is the one the experimenter changes or alters.
The effect of a daily walking program on elderly people’s lung capactiy.
The independent variable is the amount of exercise.
The dependent variable is the lung capacity.
College students’ memory for German vocabulary words is tested after a normal night’s sleep or a night of no sleep.
IDV is the amount of sleep. DV is the score on the memory test.

16. Scientific Method: 6 Rules of Conducting Experiments
-Experimental Group
-Control Group
5. Compare Measurements
6. Interpret Results and Draw Conclusions.
Control Group: The Group that is treated in the same way as the experimental group except that the independent variable is not applied.
Psychologists do not accept the results of their own or other people’s results until results have been replicated. Duplicated by at least one other psychologist with different participants.
Why? There is always a chance that studies have hidden flaws.

18. Placebo
Some intervention (pill, therapy, etc.) that resembles true medical therapy, but in fact has no medical effects
Placebo effect: a change in a patient’s illness due to imagined treatment effects

20. Case Studies: Testimonials (cont)
Disadvantages
Error and bias: our perception of events and people change when we strongly believe is something
Self-fulfilling prophecy: unconsciously making something happen due to sincere belief that it will