Question 455113
In a multiple-choice test, each question has four options. Students will get 2 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? 
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Random point values::::::::::: 2:::::-1:::0
Corresponding probabilities::: 1/4:::3/4::0
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Expected Value: (1/4)2 - (3/4)1 + 0 = (1/2)-(3/4) = -1/4 point
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The person stands to lose 1/4 point on each problem he/she answers.
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It's disadvantage to guess.
Cheers,
Stan H.