30. The length of human pregnancies from conception to birth varies according to the normal distribution with a mean of 266 days and a standard deviation of 16 days.
a. Almost all pregnancies (99.7%) of pregnancies fall within what length of days?
b. How long are the longest 2.5% of all pregnancies?
c. How short at the shortest 16% of pregnancies?
What is the probability that a pregnancy will last 272 days or longer?
e. What is the probability that a pregnancy will last 250 days or shorter?
f. What is the probability that a pregnancy will last between 250 and 290 days?
d.