The Journal of Marketing Research (October 2019) published a study of delivery times for online orders. During a recent year, a major apparel retailer fulfilled all its online orders from a single distribution center (DC) located in the eastern United States. Later that year, the retailer opened a second DC located in the western United States, with the goal of reducing delivery times to western US customers. The researchers collected data on delivery times for a sample of online orders fulfilled by both the eastern and western US distribution centers for several western states. For the state of Washington, the typical delivery time was 7 business days from the eastern DC and 5 business days from the western DC. For the state of Montana, the typical delivery time was 7 business days from either of the distribution centers.

a. What is the experimental unit for this study?

b. Identify the variables measured and their type (quantitative or qualitative).

c. Explain why this is an example of inferential statistics. What inference can you make?