Question 405117: 22) A multiple-choice test has 48 questions, each with four response choices. If a student is simply guessing at the answers,
A) What is the probably of guessing correctly for any question?
¼ = 25%
b) On average, how many questions would a student get correct for the entire test?
c) What is the probability that a student would get more than 18 answers correct simply by guessing?
d) What is the probability that a student would get 18 or more answers correct simply by guessing?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A multiple-choice test has 48 questions, each with four response choices. If a student is simply guessing at the answers,
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Binomial Problem with n=48 and p(correct)=1/4 and p(wrong)=3/4
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A) What is the probability of guessing correctly for any question?
¼ = 25%
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b) On average, how many questions would a student get correct for the entire test?
mean = np = 48*(1/4) = 12
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c) What is the probability that a student would get more than 18 answers correct simply by guessing?
P(19 <= x <= 48) = 1 - binomcdf(48,0.25,18) = 0.0184..
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d) What is the probability that a student would get 18 or more answers correct simply by guessing?
P(18<= x <= 48) = 1 - binomcdf(48,0.25,17) = 0.0374..
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Cheers,
Stan H.
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