1. Chapter 2 Notes Psychological Research Methods and Statistics
Psychology
Chapter 2 Notes
Psychological Research Methods and Statistics

2. What is Research?
Psychologists must first decide how to approach the research issue. Then they conduct the research in one of a variety of ways to test a hypothesis, solve a problem, or confirm previous findings
Pre-Research Decisions
Begin by developing a hypothesis
Look for evidence/conduct research
Researchers select a sample – a relatively small group out of the total population under study
Must be representative of the population
Choose a purely random sample
Use a stratified sample – subgroups in the population are represented proportionally

3. Methods o f Research
Naturalistic Observation – observing behaviors with out intruding or disturbing those being observed
Case studies are intensive studies of a person or group of people
Long-term observations
Diaries
Tests
Interviews
Surveys involve interviews and/or questionnaires. Very practical way to gather data

4. Longitudinal Studies occur when a psychologist studies the same group of people at regular intervals over a period of years to determine whether their behavior and/or feelings have changed and if so, how.
Cross-Sectional Studies are when psychologist organize people into groups on the basis of age
The groups are randomly sampled with simultaneously with
Surveys
Tests
Observations

5. Correlations and explanations
Correlations describe how two sets of data relate to each other
Experiments
Hypothesis – educated guess
Variables – conditions and behaviors that are subject to change
Independent variable is changed or altered so the experimenters can observe its effects
Dependent variable changes in relation to the independent variable
Experimental group – those who are exposed to the independent variable
Control group – those who are not exposed to the independent variable

6. Ethical Issues
Ethics are the methods of conduct or standard for proper and responsible behavior
Plan to minimize possible misleading results
Maintain the dignity and welfare of the participants
Obey all state, federal, and professional laws, regulations, and standards
Reach agreements regarding the rights and responsibilities of the participants and the researchers
Obtain signed, informed consent
Deception is used only if no better alternative is available

7. Problems and solutions in research
The investigation of psychological issues is a painstaking process. Psychologists must recognize and resolve errors while doing research
Self-fulfilling Prophecy
Self-fulfilling Prophecy involves having expectations about a behavior and then acting in some way, usually unknowingly to carry out that behavior
Avoiding a Self-fulfilling Prophecy
Double-blind experiment – neither the experimenter nor the participants know which participants are receiving the experimental stuff
Single-blind experiment – the participants don’t know if they’ve received the stuff or the placebo, but the experimenter does.

8. The Milgram Experiment
Stanley Milgram (1960s)
Told people to act like they were receiving electric shocks to see how the person supposedly delivering the shocks would respond
Most of those delivering the shocks continued to deliver them through the maximum capacity of electricity
Conclusion was the people will hurt others when told to do so by an authority figure
Placebo Effect
Placebo effect happens when a person’s illness or physical state changes when they simply think they are receiving treatment

9. Statistical Evaluation
Psychologists must collect and evaluate evidence to support their hypothesis.
Descriptive Statistics
Descriptive Statistics is the listing and summarizing of data in a practical, efficient way through graphs and averages
Frequency distributions are common
Frequency polygons are like line graphs that compare two sets of data
Normal Curve (aka a bell curve) is where the curve is highest in the middle and tapers off towards both ends. It is symmetrical

10. Measures of Central Tendency
Central tendency is a number that describes something about the “average” score
Mode is the most frequent score
Bimodal indicates there are two frequent scores/modes
Mean is what most people think of as an average
This is the balance point
Measures of Variance
Measures of variance provide an index of how spread out the scores of a distribution are
Standard Deviation is a better measure of variance because it uses all the data points in its calculation.

11. Correlation Coefficients describe the direction and strength of the relationship between two sets of observations
Positive correlation means as one variable increases so does the other
Negative correlation means as one variable increases, the other decreases
Scatterplots are graphs of scores on the two variables
Inferential Statistics
Inferential statistics allow researchers to determine whether the data they collect support their hypotheses, or whether their results are merely due to chance outcomes
Probability - what is the probability that something will happen?
Chance – could the results be due to chance?