SOLUTION: Assume that the mean length of a human pregnancy is 268 days with a standard deviation of 9 days. What precentage of human pregnancies do we expect to last no more than 260 days?

Question 744080: Assume that the mean length of a human pregnancy is 268 days with a standard deviation of 9 days. What precentage of human pregnancies do we expect to last no more than 260 days?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Assume that the mean length of a human pregnancy is 268 days with a standard deviation of 9 days. What precentage of human pregnancies do we expect to last no more than 260 days?
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z(260) = (260-268)/9 = -8/9
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P(x <= 260) = P(z <= -8/9) = normalcdf(-100,-8/9) = 0.1870
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Cheers,
Stan H.
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