A research study is being conducted to determine whether the addition of a vitamin A supplement will
result in weight loss. Study participants are divided into two groups, group W which receives the
vitamin A supplement and group X which does not receive the supplement. Initial weights are
obtained. Each participant follows a prescribed diet and exercise program. After a period of 2 months
each participant's weight is measured.

Control Group - ?

Independent variable - ?

Dependent variable - ?

Constants - ?