Question 292204: If a student randomly guesses on each of 25 questions he has a 1 out of 5 (20%) chance of getting a correct answer since it is a multiple choice exam with choices a,b,c,d,and e. What is the probability that the student will get 16 or more correct? What is the probability the student will get 15 or less correct?
I know that n=25 and p=.2 I tried binomial probability and computation, neither worked right. What do you suggest?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! If a student randomly guesses on each of 25 questions he has a 1 out of 5 (20%) chance of getting a correct answer since it is a multiple choice exam with choices a,b,c,d,and e. What is the probability that the student will get 16 or more correct? What is the probability the student will get 15 or less correct?
I know that n=25 and p=.2 I tried binomial probability and computation, neither worked right. What do you suggest?
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You are correct in saying n= 25 and p = 0.2
Ans: P(16 <= x <= 25) = 1 - P(0<= x <=15) = 0.000002064
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Cheers,
Stan H.
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