When testing the perceptual effects of music training, why should a researcher use random assignment of participants to a musical group or control activity?
A) Participants are usually equally glad to be assigned to any kind of activity.
B) Otherwise, the direction of causation is questionable, since those in the music group may already have superior listening skills that made them more likely to want to play music.
C) Random assignment makes the music group more diverse.
D) Random assignment minimizes individual differences within each group, making the groups easier to reason about.

Question

Quizplus · Accepted Answer

Random assignment helps to eliminate the possibility of pre-existing differences between groups, such as individuals in the music group having superior listening skills before beginning the training. This increases the internal validity of the study and ensures that any observed effects can be attributed to the music training itself, rather than other potential factors.

When Testing the Perceptual Effects of Music Training, Why Should