What does Random Group Design primarily involve?

Random Group Design primarily involves assigning subjects randomly to treatment conditions. This method is used in research to ensure that each participant has an equal chance of being placed in any group, thus minimizing bias and ensuring that the groups are comparable. By doing so, it allows researchers to make more accurate inferences about the treatment's effects because random assignment controls for individual differences that could affect the outcome.

In this design, factors like age, gender, or prior experiences are equally distributed across treatment and control groups, which helps in isolating the impact of the treatment itself. This is crucial in evaluating the efficacy of interventions, including those used in music therapy.

The other options represent different methodologies that lack the randomization aspect, which is essential for the integrity of a true experimental design. Observing behavior without any treatment intervention does not pertain to experimental manipulation. Matching groups based on baseline measurements, while it helps in controlling variables, does not achieve the randomness necessary for this design. Implementing treatment on a single subject aligns more with case studies or single-case designs rather than with Random Group Design, which involves multiple participants to generalize findings across a larger population.