The lengths of a particular animal's pregnancies are approximately normally distributed, with mean = 255 days and standard deviation σ = 12 days.
(a) What proportion of pregnancies lasts more than 270 days?
(b) What proportion of pregnancies lasts between 249 and 261 days?
(c) What is the probability that a randomly selected pregnancy lasts no more than 237 days?
(d) A "very preterm baby is one whose gestation period is less than 225 days. Are very preterm babies unusual?
Click the icon to view a table of areas under the normal curve.
(a) The proportion of pregnancies that last more than 270 days is
(Round to four decimal places as needed.)