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A multiple-choice test contains 25 questions, each with 4 answers. Assume a student just guesses on each question. (a) What is the probabili
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A multiple-choice test contains 25 questions, each with 4 answers. Assume a student just guesses on each question. (a) What is the probability that the student answers more than 20 questions correctly
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Mathematics
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2021-08-25T07:39:14+00:00
2021-08-25T07:39:14+00:00 1 Answers
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Answer:
9.68*10^-10
Step-by-step explanation:
The problem above can be solved using the binomial probability relation :
Where ;
P(x = x) = nCx * p^x * q^(n-x)
n = number of trials = 25
p = 1/4 = 0.25
q = 1 – p = 0.75
x = 20
P(x > 20) = p(x = 21) + p(x = 22) +.. + p(x = 25)
Using the binomial probability calculator to save computation time :
P(x > 20) = 9.68*10^-10