On a multiple choice test with 17 questions, each question has four possible answers, one of which is correct. For students who guess at all answers, find the mean for the number of correct answers.
A) 8.5 questions
B) 12.8 questions
C) 4.3 questions
D) 5.7 questions

Question

Quizplus · Accepted Answer

Since there are four possible answers for each question and only one of them is correct, the probability of guessing the correct answer for any question is 1/4. For 17 questions, the mean (expected value) of correct answers is 17 * (1/4) = 4.25, which rounds to 4.3 questions.

On a Multiple Choice Test with 17 Questions, Each Question