Which of the following describes a true experiment?

A true experiment is characterized by the manipulation of independent variables to observe the effect on dependent variables while employing random assignment to ensure that participants are assigned to different conditions in a way that minimizes bias. This allows researchers to establish cause-and-effect relationships.

In a true experiment, the manipulation and random assignment are critical because they enable the researcher to determine if changes in the independent variable directly lead to changes in the dependent variable. This control over experimental conditions helps to eliminate alternative explanations for the results, enhancing the validity of the findings.

The other options do not align with the principles of a true experiment. Observational data collection lacks the active manipulation of variables necessary for experimentation. Relying solely on surveys and questionnaires does not involve experimental manipulation and often leads to correlational rather than causal conclusions. The absence of a control group is contrary to experimental design, as control groups are essential for comparing outcomes and assessing the effect of the independent variable properly.