In a study designed to assess whether visualization techniques make a difference on athletic performance, basketball players who had been randomly selected were randomly assigned to either use or not use visualization for 30 minutes a day for 2 weeks in relation to making a free throw. All participants then shot 20 free throws and the total made were recorded.
What type of research method best describes this scenario (descriptive, predictive, or experimental)?
What is the independent (or subject/participant) variable?