<PRE><B>Question 409970</B>
Each day a quality engineer selects a random sample of 100 bolts from the day’s production, measures their lengths, and computes a 95% confidence interval for the mean length of all the bolts manufactured that day. What is the probability that more than 15 of the confidence intervals constructed in the next 250 days will fail to cover the true mean?
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P(a CI does cover the true mean) = 0.95
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P(it does not) = 0.05
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Binomial Problem with n = 250 and p = 0.05
P(x &gt; 15) = 1 - binomcdf(250,0.5,15) = 0.8113

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Cheers,
Stan H
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