Magnum, LLC, is a web page design firm that has two designs for an online hardware store. To determine which is the more effective design, Magnum uses one page in the Denver area and a second page in the Miami area. For each visit, Magnum records the amount of time visiting the site and the amount spent by the visitor.
(a) What is the explanatory variable in this study? Is it qualitative or quantitative?
(b) What are the two response variables? For each response variable, state whether it is qualitative or quantitative.
(c) Explain how confounding might be an issue with this study.