Horse pregnancies Bigger animals tend to carry their young longer before birth. The length of horse pregnancies from conception to birth varies according to a roughly Normal distribution with mean 336 days and standard deviation 3 days. Use the 68–95–

99.7 rule to answer the following questions.

(a) Almost all (99.7%) horse pregnancies fall in what interval of lengths?

(b) What percent of horse pregnancies are longer than 339 days? Show your work.