SOLUTION: Gestation periods of humans are normally distributed with a mean of 266 days and a standard deviation of 16 days? 1. Find the probability that a random sample of 36 pregnancies

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Question 1113090: Gestation periods of humans are normally distributed with a mean of 266 days and a standard deviation of 16 days?
1. Find the probability that a random sample of 36 pregnancies has a mean gestation period within 5 days of the mean.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Gestation periods of humans are normally distributed with a mean of 266 days and a standard deviation of 16 days?
1. Find the probability that a random sample of 36 pregnancies has a mean gestation period within 5 days of the mean.
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std of the sample means = 16/sqrt(36) = 16/6 = 8/3
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z(261) = (261-266)/(8/3) = -5/(8/3) = -1.875
z(271) = +5/(8/3) = +1.875
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p(261< x-bar <271) = P(-1.875< z <+1.875) = normalcdf(-1.875,1.875) = 0.94
Cheers,
Stan H.
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