The length of human pregnancies is approximately normal with mean u=266 days and standard deviationo=16 days. When calculating a probability, draw the graph of the normal curve and shade the appropriate area.

a. What is the probability a randomly selected pregnancy lasts less than 260 days?

b. ) Suppose a random sample of 20 pregnancies is obtained. Describe the sampling distribution of the sample mean length of human pregnancies (give the shape, mean, and standard deviation).

c. ) What is the probability that a random sample of 20 pregnancies has a mean gestation period of 260 days or less?

d. ) What is the probability that a random sample of 50 pregnancies has a mean gestation period of 260 days or less?

e. ) What might you conclude if a random sample of 50 pregnancies resulted in a mean gestation period of 260 days or less?

f. ) What is the probability a random sample of size 15 will have a mean gestations period within 10 days of the mean?