Suppose you want to determine whether or not a high dose (1 Og/day) of omega-3 fats from fish oil improve people's mood. To test the hypothesis, 30 people agreed to participate in a four- month study. Half were randomly assigned to take the fish oil and half were not. After four months, subjects were surveyed about their moods. Part a: Is this an experimental study or an observational study? Explain. Part b: What are the subjects of the study? Part c: What are the treatments? Part d: What is the response variable? Part 6: What variables need to be controlled