Before making trend decisions, launching a new product, or starting a new business, you need information to minimize your risk and enhance your chance for success. Knowledge allows you to evaluate the potential success of long-term decisions or strategies, and evaluate trends and the future needs of your industry.
Knowledge often comes in the form of data. Sometimes, existing data is sufficient, but often data needs to be gathered. Knowledge of sample survey techniques increase your likelihood of getting accurate, useable information with the least expense of time and money. In this chapter, we discuss important issues about survey sampling for the purpose of collecting information.
We start with some terminology. Data is often collected on a random sample of subjects from a target population . Consider trying to estimate the percentage of WMU undergraduates whose permanent residence is in Southwest Michigan (either Allegan, Barry, Berrien, Branch, Calhoun, Cass, Kalamazoo, Kent, Ottawa, St. Joseph, or Van Buren counties). Suppose that we want to select approximately n=200 students. There are several sampling methods available.