13.40 Kitty is the owner of Lutz Bakery in Stockholm, Sweden.

She wants to know the volume of sales of her three new cake flavors (chocolate caramel, vanilla buttercream, and blueberry glaze). She is considering the weekend sales from three different outlets that are located on Långa Gatan, Strandvägen, and Nytorget.

a. What is the treatment variable in an experimental design for the above situation? Why?

b. What are the blocking variables in the experimental design? Why?

c. Use the answers in parts a and b to create an experimental design model for Kitty that clearly defines the variables used in the model.