SOLUTION: In a multiple-choice test, each question has five options. Students will get 3 points for each correct answer; lose 1 point for each incorrect answer; and receive no points for una

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Question 421130: In a multiple-choice test, each question has five options. Students will get 3 points for each correct answer; lose 1 point 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 by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
It will be a disadvantage to guess:
The expectation is %281%2F5%29%2A3+%2B+%284%2F5%29%2A%28-1%29+=+-1%2F5.
Whereas, if he doesn't answer the question, his expectation is 0.