A Museum Is Interested in Determining Which Particular Pieces of Art

Multiple Choice

A museum is interested in determining which particular pieces of art are the most popular but does not want to directly ask its patrons. Instead, the head of the museum decides to keep track of the wear on the carpet in front of each of the pieces, assuming that the more popular pieces will have more worn carpet in front of them. This particular way of measuring art popularity is making use of a(n)

A) confounding variable
B) placebo
C) representative sample
D) unobtrusive measure