Have you ever been selected as a respondent in a marketing research survey?

Have you ever been selected as a respondent in a marketing research survey? If yes, how were you contacted and where were you interviewed? Why do you think you, in particular, were selected? Did you know or could you guess the purpose of the survey? Do you know the name of the company or brand involved in the survey?

2. What is the difference between primary and secondary research? Under what circumstances might the availability of secondary data make primary research unnecessary? What are some major sources of secondary data?