Question

the lengths of pregnancies are normally distributed with a mean of 269 days and a standard deviation of 15 days.
a. in a letter to an advice column, a wife claimed to have given birth 309 days after a brief visit from her husband, who was working in another country. find the probability of a pregnancy lasting 309 days or longer. what does the result suggest?
b. if the length of pregnancy is in the lowest 3%, then the baby is premature. find the length that separates premature babies from those who are not considered premature.

a. the probability that a pregnancy will last 309 days or longer is
(round to four decimal places as needed.)

Explanation:

Calculate the z-score

$$
LATEXBLOCK0
$$

Find the cumulative probability

$$
LATEXBLOCK1
$$

Answer:

a. The probability that a pregnancy will last 309 days or longer is <blank>0.0038</blank>