You test whether some types of exercise are better for controlling depression. your participants are people with mild depression. you randomly assign participants to either practice yoga for 7 hours/week, or to do weight training for 4 hours/week. depression is measured using the beck depression inventory.
what is the operational definition of the dependent variable?

depression, yoga 7 hours/week and weight training 4 hours/week, people with mild depression, or the beck depression