
Good point.
Although, I would get the exact same results surveying people at school. They sell both drinks at the cafeteria where I go to school for cheap (they sell the mini-bottles), so most everyone that I talk to at school has tried both at least once.
Plus, I'm not using just these results. I'm doing the project with a partner and we're each responsible for surveying 60 people each. My friend is surveying her friends at her church, which is extreme upper class. She goes to church in the most wealthy part of my town. George W. Bush lives there now - he just bought a house there.
Also, it's better than the majority of my class. They're all making up their results.