What is the design of the following study? The Coca-Cola Company introduced New Coke in 1985. Within three months of this introduction, negative consumer reaction forced Coca-Cola to reintroduce the original formula of Coke as Coca-Cola Classic. Suppose that two years later, in 1987, a marketing research firm in Chicago compared the sales of Coca-Cola Classic, New Coke, and Pepsi in public building vending machines. To do this, the marketing research firm randomly selected 10 public buildings in Chicago having both a Coke machine (selling Coke Classic and New Coke) and a Pepsi machine. The researchers recorded the number of cans sold over a given period of time.

The researchers used a randomized design for this study. While designing a research experiment, we use a randomized design to study the effect that a major factor or a primary factor would have without having the need to use any unrelated or unnecessary variable. The question tells us that ten public buildings that have a coke machine and a Pepsi machine were selected for the study.