Corrosion prevention of buried steel structures. Engineers have designed tests on underground steel structures that measure the potential for corrosion. In Materials Performance (Mar. 2013), two tests for steel corrosion—

called “instant-off” and “instant-on” potential—were compared. The tests were applied to buried piping at a petrochemical plant. Both the “instant-off” and “instant-on”

corrosion measurements were made at each of 19 different randomly selected pipe locations. One objective of the study is to determine if one test is more desirable (i.e., can more accurately predict the potential for corrosion) than the other when applied to buried steel piping.

a. What are the experimental units for this study?

b. Describe the sample.

c. Describe the population.

d. Is this an example of descriptive or inferential statistics?