Question 418039: On a multiple choice test with 29 questions, each question has four possible answers, one of which is correct. For students who guess at all answers, find the MEAN, and the STANDARD DEVIATION, for the number of correct answers.
That is the question I need to solve for a practice test. I do not know how to begin. I Have used N=29... but that is all I have done.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! On a multiple choice test with 29 questions, each question has four possible answers, one of which is correct. For students who guess at all answers, find the MEAN, and the STANDARD DEVIATION, for the number of correct answers.
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Binomial Problem with n=29 and p = 1/4
mean = np = 29(1/4) = 7 1/4
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std = sqrt(npq) = sqrt((29/4)(3/4)) = sqrt(3*29/16) = sqrt(57)/4
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Cheers,
Stan H.
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