What distinguishes experimental from correlational designs?

What distinguishes experimental from correlational designs?

• A. Random assignment to different groups.
• B. Observing naturally without intervention.
• C. Manipulating all variables.
• D. No variables measured.

Answer: (A)

Random assignment to different groups distinguishes experimental designs from correlational ones. In an experiment, the independent variable is actively manipulated and participants are randomly placed into conditions, which helps ensure the groups are equivalent at the start. This control makes it possible to attribute differences in the outcome to the manipulation itself, supporting causal conclusions. In contrast, correlational designs involve observing variables as they occur without intervention or random assignment, so they can show associations but not causation. The other statements describe features not unique to experiments: observing naturally without intervention fits correlational work; manipulating all variables is not how experiments are conducted (usually only a key variable is manipulated); and measuring variables is always part of experiments to assess outcomes.

Random assignment to different groups distinguishes experimental designs from correlational ones. In an experiment, the independent variable is actively manipulated and participants are randomly placed into conditions, which helps ensure the groups are equivalent at the start. This control makes it possible to attribute differences in the outcome to the manipulation itself, supporting causal conclusions. In contrast, correlational designs involve observing variables as they occur without intervention or random assignment, so they can show associations but not causation. The other statements describe features not unique to experiments: observing naturally without intervention fits correlational work; manipulating all variables is not how experiments are conducted (usually only a key variable is manipulated); and measuring variables is always part of experiments to assess outcomes.