Astronomy final exam question: the Drake equation

Astronomy 210 Final Exam, Fall Semester 2008
Cuesta College, San Luis Obispo, CA

[4.0 points.] The Drake equation estimates the number of technological civilizations in the Milky Way by:
(A) estimating the number of inhabited planets, and lifetimes of technological civilizations.
(B) estimating the number of possible signals receivable by radio telescopes.
(C) extrapolating the past progress of Earth technology.
(D) assuming that it is impossible for there to be only one technological civilization.

Section 70158
(A) : 51 students
(B) : 10 students
(C) : 3 students
(D) : 5 students

Correct answer: (A)

Response (A) is the definition of the Drake equation.

This was asked previously this semester as a quiz question.

"Difficulty level": 64% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33