Question 329255: A 20 question multiple-choice test has four possible answers for each question (A, B, C, or D). Suppose that you don't know the answers to any of the questions so you have to guess on each question. Then this situation follows a binomial distribution where X is the number of questions you get correct out of 20.
Find the probability that you get exactly 2 questions correct on the test.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A 20 question multiple-choice test has four possible answers for each question (A, B, C, or D). Suppose that you don't know the answers to any of the questions so you have to guess on each question. Then this situation follows a binomial distribution where X is the number of questions you get correct out of 20.
Find the probability that you get exactly 2 questions correct on the test.
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Binomial with n = 20 and p = 1/4
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P(x = 2) = 20C2(1/4)^2*(3/4)^18 = 0.0669
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Cheers,
Stan H.
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