The manager of a shopping center wishes to obtain information on the shopping habits of people in the area. The area contains four neighborhoods of varying populations. The manager suspects that the shopping habits may be different in different-sized neighborhoods. Which of the following sampling designs would be most effective in gathering the information the manager requires?
A. a convenience sample from the area
B. a simple random sample from the area
C. a cluster sample using the neighborhoods as clusters
D. a stratified sample from the neighborhoods in the area
E. an online poll that invites all people from the neighborhoods in the area to participate