Which of the following statements is/are true?
I. Correlation and regression require explanatory and response variables.
II. Scatterplots require that both variables be quantitative.
III. Every least-squares regression line passes through (X bar, Y bar).
a. I and II only
b. I and III only
c. II and III only
d. I, II, and III
e. None of the above
Answer: c. II and III only