RESEARCH METHODS PART II

ESSENTIAL VOCABULARY

Theory: an explanation using an integrated set of principles that organize observations and predicts behaviors or events.

Hypothesis: a testable prediction, often implied by a theory.

More Key Vocabulary

Operational Definition: a statement of the procedures (operations) used to define research variables.

Replication: repeating the essence of a research study.

Case Study: one person is studied in depth in the hope of revealing universal principles.

How Do Psychologists Study Behavior?

How Do Psychologists Study Behavior Part II

Case Study: an observational technique in which one person is studied in depth in the hope of revealing universal principles

What are the strengths and weaknesses of Case Studies?

The Funniest Weakness

“I have an uncle who smoked two packs a day and lived to be 89.”

“I know a man who dreamed his sister was in a car accident and two days later she died in a

head-on collision.”

These statements can often be true and are also very memorable to people.

Surveys

Survey (defined): a technique for ascertaining the self-reported attitudes or behaviors of a particular group, usually questioning a representative, random sample of the group.

When Surveys are Useful

Surveys are used when researchers want to estimate from a representative sample of people, the attitudes or reported behaviors of a whole population.

Correlation Revisited

Describing behavior is the first step toward predicting it. Surveys often show us that one trait or behavior is related to another. In such cases we say that the two correlate.

Scatterplots graphically show the relationship between 2 variables.

Scatterplots

Correlation Coefficient

A statistical index of the relationship between 2 things from -1 to +1.

Perfect Positive Correlation: +1

No relationship: 0

Perfect Negative Correlation -1

What is the difference in these 2 graphs?

The previous slide shows that we’d get the same negative correlation between low self-esteem and depression if depression caused some people to be down on themselves or if some third factor such as heredity or brain chemistry—caused both low self-esteem and depression.

Correlation does not = Causation

The more years that a man has been married is correlated to hair loss.

Does marriage cause hair loss?