The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a standard deviation of 15 days. Find the probability of a pregnancy lasting less than 250 days.
A)0.1151
B)0.1591
C)0.0606
D)0.0066

Question

Quizplus · Accepted Answer

The probability of a pregnancy lasting less than 250 days is the area under the normal distribution curve to the left of 250 days. This area is given by the cumulative distribution function (CDF) of the normal distribution, which can be calculated using a calculator or a statistical software package. The CDF of the normal distribution with mean 268 and standard deviation 15 is 0.1151 at 250 days. Therefore, the probability of a pregnancy lasting less than 250 days is 0.1151.

The Lengths of Pregnancies of Humans Are Normally Distributed with a Mean