Chapter 2i

Hypothesis

A testable prediction often implied by a theory.

Dependent Variable

The variable that depends on the independent variable; it is measured in an experiment.

Independent Variable

The variable in an experiment that is changed or manipulated.

Theory

An explanation using an integrated set of principles that organizes observations and predicts behaviors or events.

Operational Definition

Specific explanations of terms used in a research study, clarifying what is measured.

Validity

When the measurement accurately reflects the concept being measured.

Reliability

The consistency of a measure across multiple tests; results can be replicated.

Replication

Repeating a research study to see if findings can be reproduced in other settings.

Population

The entire group from which a sample is drawn for research.

Sampling

The process of selecting participants for a study.

Random Selection

A sampling technique where every member of the population has an equal chance of being selected.

Stratified Sampling

A sampling method that selects participants according to specific subgroups within the population.

Experimental Method

A research method that tests causal relationships among variables by manipulating one or more independent variables.

Confounding Variable

An extraneous variable that influences the dependent variable and may lead to incorrect conclusions.

Naturalistic Observation

Researching behavior in its natural environment without interference.

Case Study

A detailed examination of a single individual or group, providing in-depth insights.

Survey

A method of gathering data by asking questions to a sample representative of a larger group.

Control Group

The group in an experiment that is not exposed to the treatment, used for comparison.

Experimental Group

The group in an experiment that receives the treatment or intervention.

Placebo Effect

The phenomenon where participants experience changes simply because they believe they are receiving treatment.

Double-blind procedure

An experimental design in which both participants and researchers are unaware of group assignments to prevent bias.

Correlation

A statistical measure that describes the extent to which two variables are related.

Scatterplot

A graph used to display the relationship between two quantitative variables.

Correlation Coefficient

A statistical index ranging from -1 to +1 that indicates the strength and direction of a relationship between two variables.

Descriptive Statistics

Statistical methods used to summarize and describe the characteristics of a data set.

Standard Deviation

A measure of how much scores in a data set deviate from the mean.

P value

The probability level used to determine statistical significance.

Z score

A statistical measure that describes a value's relationship to the mean of a group of values.

Informed consent

The process of informing participants about the details of a study before they agree to partake.

Confidentiality

The ethical principle where personal information about participants is kept private.