Suppose that 10,000 customers in a retailer’s customer database are categorized by three customer types: 3,500 prospective buyers, 4,500 first time buyers, and 2,000 repeat (loyal) buyers. A sample of 1,000 customers is needed.
a. What type of sampling should you do? Why?
b. Explain how you would carry out the sampling according to the method stated in (a).
c. Why is the sampling in (a) not simple random sampling?