Scientific Method: Variables, Hypotheses, and Experiment Types

Vocabulary flashcards covering the components of experimental design, including independent, dependent, and controlled variables, hypothesis formation, experimental vs. control groups, and types of experimental studies.

Variable

Any factor that could affect the results of what you are studying, used as an experimental tool to track what is going on, gain control, and make conclusions more reliable.

Independent variable

The variable that the investigator changes or manipulates; an experiment usually has only one.

Dependent variable

The variable that responds or reacts as a result of the change in the independent variable; an experiment can have more than one.

Controlled variables

Variables that remain constant (unchanged) during an experiment to ensure that results are reliable and not caused by outside factors.

Hypothesis

A possible explanation or prediction for an observation based on limited evidence that serves as a starting point for further investigation, is developed from an original question, and is based on prior knowledge.

If… then… because… format

The standard structure of a hypothesis that connects a specific change in the independent variable to a predicted response in the dependent variable, followed by an explanation based on prior knowledge.

Control group

The group in an experiment that serves as the comparison or "baseline," remaining identical to the experimental group except that the variable being tested is unchanged ("always off" or "always on").

Experimental group

The group in an experiment that receives the treatment to show the effect of the variable being tested.

Controlled Experiment

A type of experiment in which the experimenter controls or accounts for nearly all aspects and alters only one variable at a time, allowing cause-and-effect relationships to be determined and causation to be claimed.

Causation

A relationship where one action or event directly causes a change or result in another.

Quasi-Experiment

An experiment where a variable is tested without randomization or where the experiment is uncontrolled, often used when variables cannot be controlled due to ethical issues or logistical difficulties.

Randomization

The process of assigning participants to different test groups by chance rather than by human choice.

Observational Study

A study design where the experimenter cannot control any variables and simply observes, collects, and analyses data, often utilized when experimental manipulation presents ethical issues.