SOLUTION: Consider a binomial experiment with 20 trials and probability 0.45 on a single trial. Use an approximation to the normal distribution to find the probability of exactly 10 successe

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Question 475492: Consider a binomial experiment with 20 trials and probability 0.45 on a single trial. Use an approximation to the normal distribution to find the probability of exactly 10 successes. Round your answer to the thousandths place. (Remember this means you will need to find the endpoints and then find a z-score for each and subtract the two areas).
Answer by stanbon(75887) About Me  (Show Source):
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Consider a binomial experiment with 20 trials and probability 0.45 on a single trial. Use an approximation to the normal distribution to find the probability of exactly 10 successes. Round your answer to the thousandths place. (Remember this means you will need to find the endpoints and then find a z-score for each and subtract the two areas).
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u = np = 20*0.45 = 9
std = sqrt[npq] = sqrt[9*0.55] = 2.1
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P(x = 10) = P(9.5 < x < 10.5)
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z(9.5) = (9.5-9)/2.1 = 0.5/2.1 = 0.2381
z(10.5) = (10.5-9)/2.1 = 0.7143
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P(x=10) = P(0.2381 < z < 0.7143) = 0.1684
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Cheers,
Stan H.
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