Dr. Einhardt wonders if taking a Vitamin D supplement would decrease the number of muscle injuries seen in basketball players. To test this, he chooses a random sample of players and divides them into 2 groups. Group A gets a Vit D supplement every day for 3 months. Group B does not get a Vit D supplement. During the three months, Dr. E records any muscle injuries diagnosed to members of each group. His hypothesis is , "Players who receive Vit D supplementation will have fewer muscle injuries than those who do not receive supplementation. The level of measurement used in this study is ______________. Group of answer choices nominal ratio interval ordinal