Question

provide an appropriate response. use the standard normal table to find the probability. 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. 0.0066 b. 0.1151 c. 0.0606 d. 0.1591

Explanation:

Step1: Calculate the z - score

The formula for the z - score is $z=\frac{x-\mu}{\sigma}$, where $x = 250$, $\mu=268$, and $\sigma = 15$. So $z=\frac{250 - 268}{15}=\frac{- 18}{15}=-1.2$.

Step2: Look up the z - score in the standard normal table

We look up the value of $z=-1.2$ in the standard - normal table. The table gives the area to the left of the z - score. The area corresponding to $z = - 1.2$ is $0.1151$.

Answer:

B. 0.1151