Question

A multiple choice test consists of 7 questions. Each question has answer choices of a,b,c, and d, and only one of the choices is correct. If a student randomly guesses on each question, what is the probability that he gets at most 2 of them correct?

Answer 1

A multiple-choice test consists of 9 questions. Each question has answer choices of a, b, c, d, and e, and only one of the choices is correct. If a student randomly guesses on each question, what is the probability that she gets fewer than 2 of them correct?
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Binomial Problem with n = 9 and p(correct) = 1/5
Hope this helps!
Answer n= 9 and p(correct)= 1/5

Answer 2

0.7564

Explanation:

Since, we know that in this case, P(correct) is 1/4 because we have four options i.e. a, b, c, and d and number of mcqs 'n' is 7. So, we can use this permutations formula:

P(0 <= x <= 1) = binomcdf(7,1/4,2) = 0.7564

Hence, the probability of getting atleast 2 of them correct is 0.7564.