Glossary
Causation
A relationship where one variable directly influences or produces a change in another variable.
Example:
An experiment might demonstrate that a specific medication causes a reduction in anxiety symptoms, rather than just being related to it.
Confounding Variables
Factors other than the independent variable that might produce an effect in an experiment, making it difficult to determine the true cause of the observed outcome.
Example:
In a study testing a new energy drink, if participants also started exercising more, the increased exercise would be a confounding variable that could affect their energy levels, not just the drink.
Control Group
In an experiment, the group that does not receive the treatment or manipulation of the independent variable; it serves as a baseline for comparison.
Example:
When testing a new fertilizer, one set of plants would receive the fertilizer (experimental group), while another set, the control group, would receive only water to see the difference.
Correlation
A statistical measure that describes the extent to which two variables change together, indicating a relationship but not necessarily cause and effect.
Example:
Researchers might find a positive correlation between the amount of time spent studying and higher exam scores, meaning they tend to increase together.
Correlational Research
A research method that examines the extent to which two or more variables are naturally associated or related, but does not establish cause and effect.
Example:
A study investigating the link between hours of sleep and reported happiness levels would be using correlational research to see if these two factors tend to change together.
Dependent Variable
The factor that is measured in an experiment; it is the outcome that may change in response to manipulations of the independent variable.
Example:
If a study examines how different teaching methods affect test scores, the test scores themselves would be the dependent variable.
Descriptive Research
A research method used to observe and record behavior or characteristics without manipulating variables or looking for relationships between them.
Example:
A psychologist conducting a descriptive research study might observe children's play behaviors in a natural setting and simply record what they see, without trying to explain why.
Experimental Research
A research method where the investigator manipulates one or more independent variables to observe their effect on some behavior or mental process, while controlling other relevant factors.
Example:
To determine if a new medication reduces depression, researchers would use experimental research, giving one group the medication and a control group a placebo, then comparing their outcomes.
External Validity
The extent to which the findings of a research study can be generalized to other populations, settings, and situations outside of the specific study.
Example:
If a study on a new teaching method only involves students from one specific school, its external validity might be limited when trying to apply it to all students nationwide.
Independent Variable
The factor that is manipulated or changed by the researcher in an experiment to see if it causes a change in another variable.
Example:
In an experiment testing the effect of caffeine on alertness, the amount of caffeine given to participants would be the independent variable.
Internal Validity
The extent to which a study establishes a trustworthy cause-and-effect relationship between the independent and dependent variables, free from the influence of confounding variables.
Example:
Careful control of all variables in an experiment helps ensure high internal validity, making researchers confident that the independent variable truly caused the observed changes.
Random Assignment
A procedure used in experiments to ensure that each participant has an equal chance of being placed into any group (e.g., experimental or control), minimizing pre-existing differences between groups.
Example:
To ensure fairness and reduce bias, participants in a drug trial are typically assigned to either the treatment or placebo group through random assignment.