Suppose the lengths of the pregnancies of a certain animal are approximately normally distributed with mean 11 = 159 days and standard deviation 6 = 8 days. Click here to view the standard norrnai distribution table (page 1). Click here to view the standard normal distribution table (Egg); E) (a) What is the probability that a randomly selected pregnancy lasts less than 156 days? The probability that a randomly selected pregnancy lasts less than 156 days is approximately '3. (Round to four decimal places as needed.) (b) What is the probability that a random sample of 15 pregnancies has a mean gestation period of 156 days or less? The probability that the mean of a a random sample of 15 pregnancies is less than 156 days is approximately D. (Round to four decimal places as needed.) (c) What is the probability that a random sample of 39 pregnancies has a mean gestation period of 156 days or less? The probability that the mean of a a random sample of 39 pregnancies is less than 156 days is approximately D. (Round to four decimal places as needed.)