Assume that the duration of human pregnancies can be described by a Normal model with mean 268 days and standard deviation 13 days. a) What percentage of pregnancies should last between 273 and 285 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 68 pregnant women. Let y represent the mean length of their pregnancies. According to the Central Limit Theorem what's the distribution of this sample mean v? Specify the model mean and standard deviation a) The percentage of pregnancies that should last between 273 and 285 days is%. (Round to two decimal places as needed.)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 260 days? a) The percentage of pregnancies that should last between 273 and 285 days is |%. (Round to two decimal places as needed.)