Question 345069: from past experience, the pass rate of students has been 70%. if 8 students are randomly selected.
a) what is the probability at least half will fail?
b) what is the standard deviation of the distribution?
c)what is the probability that no student will fail?
d0 state the name given to the probability distribution being described in the question and state one of its characteristics?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! from past experience, the pass rate of students has been 70%. if 8 students are randomly selected.
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Binomial Problem with n = 8 and p = 0.7
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a) what is the probability at least half will fail?
P(4<= x <=8) = 1-binomcdf(8,0.7,3) = 0.9420
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b) what is the standard deviation of the distribution?
std = sqrt(npq) = sqrt(8*0.7*0.3) = 1.2961
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c)what is the probability that no student will fail?
P(x = 0) = 0.7^8 = 0.0576
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d) state the name given to the probability distribution being described in the question and state one of its characteristics?
binomial; n independent trials.
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Cheers,
Stan H.
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