Researchers found that students who claimed to have never pulled an all-nighter had an average GPA of 3.1, compared to 2.9 for those students who do claim to have pulled all-nighters.
a. In this context, what is the observational unit?
A. Researcher
B. Student
C. GPA
D. Whether or not have pulled an all-nighter

b. Which of the following is the explanatory variable?

A. Whether or not have pulled an all-nighter
B. Student
C. GPA
D. Th ose students who have pulled all-nighters

c. Which of the following is the response variable?
A. GPA
B. Average GPA
C. Whether or not have pulled an all-nighter
D. Students who have pulled all-nighters tend to have lower GPAs, on average.

d. The explanatory variable is ________ (categorical/ quantitative).
e. The response variable is ________ (categorical/ quantitative).

Refer to a study published in the January 2008 issue of Behavioral Sleep Medicine that involved a survey of 120 students at St. Lawrence University, a small liberal arts college in upstate New York.