The authors of the article cited in the previous exercise surveyed 300 wine consumers, each of whom tasted two different wines. For each individual in the study, the following information was recorded:
a. Gender
b. Age, in years
c. Monthly income, in euros
d. Educational level (primary, secondary, or university)
e. Willingness to pay (WTP) for the first wine tasted, in euros
f. WTP for the second wine tasted, in euros. (WTP is a very common measure for consumer products. Researchers ask, “How much would you be willing to pay for this item?”) Classify each of the variables (a)– (f) as quantitative or categorical.