Work in pairs.
The general problem that you're investigating is the purchasing habits of individuals who are shopping in the produce sections at several types of markets: US-style supermarket, Farmer's market, and an Ethnic market.
You need to collect some demographic information as well as data to test several hypotheses.
Note that this must fit within the constraints of the Human Subjects guidelines and be culturally sensitive.
Consider, also, whether the person running the market would allow you to use your questionnaire.
Present your questionnaire to the group for a critique.