Lecture Notes Review: Theories, Hypotheses, Operational Definitions, Experimental Design, Correlation

A set of practice questions and answers covering theories vs hypotheses, operational definitions, experiments, IV/DV, random assignment, and correlations.

How does a theory differ from a hypothesis?

A theory is broad and abstract; a hypothesis is a specific, testable prediction derived from the theory.

What is an operational definition?

Defining an abstract variable in measurable, observable terms for a study.

In the discussed frustration study, what operational definitions were used to indicate high versus low frustration?

High frustration: being prevented from finishing a task; low frustration: not being prevented from finishing.

What is the goal of an experiment?

To determine if one variable (X) causes a change in another (Y) by manipulating X and observing Y.

In the sleep and athletic performance study, what are the independent and dependent variables?

Independent variable: amount of sleep (9, 5, or 3 hours). Dependent variable: athletic performance, operationally measured as ability scores on events (e.g., running, batting, throwing).

What is an experimental group versus a control group?

Experimental group: receives the independent variable's manipulation. Control group: receives no manipulation, serving as a baseline.

What is random assignment and its purpose?

Random assignment places participants in groups so they are equivalent at the start, balancing individual differences.

What is a correlational study?

A study that examines relationships between two or more variables without manipulating them, focusing on direction and strength of relationships.

How is correlation strength quantified and what are the possible values?

Quantified by a correlation coefficient ranging from -1 to +1. Magnitude (closer to ±1) shows strength; sign (positive/negative) shows direction.

Can a correlation imply causation?

No; correlation shows association, not causation, in correlational studies.

What does a strong negative relationship look like with self-esteem and depression?

As self-esteem increases, depression tends to decrease; a strong negative correlation (closer to -1).

What is a perfect correlation?

A correlation of +1 or -1, meaning one variable perfectly predicts the other.

What does a correlation of +0.75 and a correlation of -0.75 signify?

Both indicate a strong relationship (0.75 magnitude is high); the sign indicates direction (positive vs negative).

What is the interpretation of a positive correlation between temperature and ice cream sales?

Higher temperature is associated with higher ice cream sales; a positive relationship.

How can you distinguish the IV and DV in a study description?

The IV is the variable the experimenter manipulates; the DV is what is measured or scored as an outcome.

Why randomly assign participants to distraction conditions?

To ensure equivalence between groups before manipulation, so any observed differences are due to the distraction.

In a three-sleep-level design, which groups are experimental and which is the control?

The 9-hour and 5-hour groups are experimental (different sleep levels); the 3-hour group is the control (baseline).

What does it mean to 'operationalize' a variable?

Defining a variable in concrete, observable terms or measurements for a study.

What does the statement 'X causes Y' refer to in experimental design?

X is the independent variable (cause), and Y is the dependent variable (effect).

What does a zero correlation imply about the relationship between two variables?

No linear relationship exists between them.