A legendary story on college campuses concerns two students who miss a chemistry exam because of excessive partying but blame their absence on a flat tire. The professor allowed them to take a make-up exam, and he sent them to separate rooms to take it. The first question, worth five points, was quite easy. The second question, worth ninety-five points, asked: Which tire was it?

Give some information about the sample of individuals that participated in our study and how the sample data were collected.

What are the observational units?

What is the variable that is measured/recorded on each observational unit?