Problema Solution
In a multiple-choice test, each question has four options. Students will get 10 points for each correct answer; lose four points for each incorrect answer; and receive no points for unanswered questions. A student does not know the correct answer for one question. Is it to her advantage or disadvantage to guess an answer? Show your calculations for expected value.
Answer provided by our tutors
Expected value of guessing = (4 points)(0.25) + (-1 point)(0.75) = 0.25 points.
Expected value of leaving unanswered = 0 points.
Her expected score will be higher if she guesses.