Psych 1005 chapter 2

Empiricism

The belief that knowledge comes from sensory experience and observation.

Scientific method

A systematic approach to research involving observation, hypothesis formation, experimentation, and result analysis.

Theories

Broad explanations and predictions concerning phenomena of interest.

Hypothesis

A testable prediction about the relationship between variables.

Empirical method

A way of acquiring knowledge based on direct observation or experience.

Operational definition

Defining a variable in terms of the specific procedures used to measure or manipulate it.

Construct validity

The extent to which a measure assesses the theoretical construct it intends to measure.

Power

The probability of finding a statistically significant result when a true effect exists.

Reliability

The consistency or repeatability of a measure.

Demand characteristics

Cues in a study that may lead participants to guess the researcher's hypotheses.

Naturalistic observation

Studying behavior in its natural context without interference.

Observer bias

Systematic errors in observation due to the researcher's expectations.

Double-blind study

A study where neither the participants nor the researchers know who is in the experimental or control group.

Population

The entire group of individuals a researcher is interested in studying.

Sample

A subset of the population selected for a study.

Frequency distribution

A summary of how often different scores occur in a dataset.

Normal distribution

A symmetrical, bell-shaped curve that represents the pattern in which many characteristics are dispersed in the population.

Mode

The most frequently occurring score in a distribution.

Mean

The average of a set of scores.

Median

The middle score in a distribution.

Range

The difference between the highest and lowest scores in a distribution.

Standard deviation

A measure of how spread out scores are around the mean.

Variable

A factor that can change in an experiment.

Correlation

A measure of the relationship between two variables.

Correlation coefficient (r)

A statistical measure of the strength and direction of a relationship between two variables.

Natural correlation

The relationship between two variables that exists in the real world.

Third-variable problem

The possibility that a third variable is influencing the relationship between two other variables.

Experimentation

The manipulation of variables to assess cause-and-effect relationships.

Manipulation

Changing a variable in an experiment to see its impact.

Independent variable

The variable that is manipulated in an experiment.

Dependent variable

The variable that is measured in an experiment.

Self-selection

A problem that occurs when participants choose their own group to be in a study.

Random assignment

Assigning participants to experimental and control groups by chance.

Internal validity

The extent to which an experiment allows for causal inferences.

External validity

The extent to which the results of a study can be generalized to other situations or populations.

Case method

A research method that involves an in-depth study of one or a few individuals.

Random sampling

Selecting a sample from a population in a way that every individual has an equal chance of being chosen.

Replication

Repeating a study to see if the results are consistent.

Type I error

Incorrectly rejecting a true null hypothesis.

Type II error

Incorrectly failing to reject a false null hypothesis.

Informed consent

Participants' agreement to take part in a study after being informed about the research.

Debriefing

Providing participants with information about the study's purpose and methods after its completion.