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Homework: 7.2 The lengths of a particular animal's pregnancies are approximately normally distributed, with mean u = 274 days and standard deviation o = 12 days. (a) What proportion of pregnancies lasts more than 292 days? (b) What proportion of pregnancies lasts between 271 and 280 days? (c) What is the probability that a randomly selected pregnancy lasts no more than 268 days? (d) A "very preterm" baby is one whose gestation period is less than 256 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 292 days is .0668 . (Round to four decimal places as needed.)