The observation method for gathering research data is most effective for:
1. Identifying the target markets for an air refresher.
2. Deciding whether to package dog food in a green or a brown bag.
3. Proving that the ad copy for a all-natural baby food communicated effectively with its target market.
4. Determining the potential sales of a cellular phone weighing just three ounces.
5. Determining how people act while waiting in a bank line.
Answer: 5. Determining how people act while waiting in a bank line.