SOLUTION: Suppose that an admission test for a certain university is designed so that the probability of passing it is 60%. Find the probability that among 20 candidates who take the test,

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Question 418574: Suppose that an admission test for a certain university is designed so that the probability of passing it is 60%. Find the probability that among 20 candidates who take the test, more than 10 will pass.
Found 2 solutions by stanbon, ewatrrr:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Suppose that an admission test for a certain university is designed so that the probability of passing it is 60%. Find the probability that among 20 candidates who take the test, more than 10 will pass.
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Binomial Problem with n = 20 and p = 0.6
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P(11 <= x <= 20) = 1-binomcdf(20,0.6,10) = 0.7554
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Cheers,
Stan H.
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Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

Note: The probability of x successes in n trials is: 

P = nCx* p%5Ex%2Aq%5E%28n-x%29 where p and q are the probabilities of success and failure 

respectively. In this case p = .60 and q = .40

nCx = n%21%2F%28x%21%28n-x%29%21%29  n = 20 and x = 10

P(>10 passing out of 20) = .7553 = P(11) + P(12)+...P(20)

for example:

P(11)= 167960(.6)^11).4)^9 = .1597    | 20C11 = 167960