SOLUTION: A survey asked a random sample of 1450 children if they support Sponge Bob being cancelled. Let X denote the number of children in the sample that they support the cancellation. Su

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Question 826724: A survey asked a random sample of 1450 children if they support Sponge Bob being cancelled. Let X denote the number of children in the sample that they support the cancellation. Suppose that 20% of all children support the cancellation. What is the probability that X is more than 450?
So far I have, P(X>450). I'm not sure where to go from here. Thanks!
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A survey asked a random sample of 1450 children if they support Sponge Bob being cancelled. Let X denote the number of children in the sample that they support the cancellation. Suppose that 20% of all children support the cancellation. What is the probability that X is more than 450?
So far I have, P(X>450). I'm not sure where to go from here.
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Binomial Problem with n = 1450 and p(support) = 0.2
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Use a normal approximation::
mean = np = 1450*0.2 = 290
std = sqrt(npq) = sqrt(290*0.8) = 15.23
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z(450) = (450-290)/15.23 = 10.50
P(x > 450) = P(z > 10.5) = 0 to eight decimal places.
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Cheers,
Stan H.