Homework: Chapter 17 HWK, ( Question 20. 17.ce.51-T , \"1:':51'54''24'39 Part 1 Part 1 OH p 0 Points: 0 of 2 Assume that the duration of human pregnancies can be described by a Normal model with mean 264 days and standard deviation 18 days. ' a) What percentage of pregnancies shoutd last between 270 and 277 days? b) At least how many days should the longest 30% of all pregnancies last? c) Suppose a certain obstetrician is currently providing prenatal care to 51_pregnant women. Let )7 represent the mean length of their pregnancies. According to the Central Limit Theorem, what's the distribution of this sample mean, y? Specify the model. mean. and standard deviation. d) What's the probability that the mean duration of these patients' pregnancies will be less than 255 days? v <:> a) The percentage of pregnancies that should last between 270 and 277 days is [:1%. (Round to two decimal places as needed.) %