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

Algebra.Com
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)   (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.
-----
std of the sample means = 16/sqrt(36) = 16/6 = 8/3
--------
z(261) = (261-266)/(8/3) = -5/(8/3) = -1.875
z(271) = +5/(8/3) = +1.875
-----
p(261< x-bar <271) = P(-1.875< z <+1.875) = normalcdf(-1.875,1.875) = 0.94
Cheers,
Stan H.
------------

RELATED QUESTIONS

Lengths of pregnancies of humans are normally distributed with a mean of 268 days and a... (answered by funmath,Edwin McCravy)
the length of pregnancies of humans are normally distributed with a mean of 169 days and... (answered by ewatrrr)
The lengths of pregnancies in a small rural village are normally distributed with a mean... (answered by ikleyn,math_tutor2020)
The lengths of pregnancies of humans are normally distributed with a mean of 268 days and (answered by khwang)
the lenghts of pregnancies of humans are normally distributed with a mean of 268 days and (answered by robertb)
The lengths of pregnancies are normally distributed with a mean of 268 days and a... (answered by stanbon)
The length of human pregnancies varies normally with a mean of 266 days and a standard... (answered by Fombitz)
The lengths of pregnancies are normally distributed with a mean of 266 days and a... (answered by Boreal)
the length of pregnancies of humans are normally distributed with a mean of 268 days and... (answered by ewatrrr)