Suppose the lengths of the pregnancies of a certain animal are approximately

normally distributed with mean mu equals 131 days


μ=131 days and standard deviation sigma equals 8 days


σ=8 days. Complete parts? (a) through? (f) below.
?(a) What is the probability that a randomly selected pregnancy lasts less than 128


128 ?days?
The probability that a randomly selected pregnancy lasts less than 128


128 days is approximately
0.352


0.352. ?(Round to four decimal places as? needed.)
Interpret this probability. Select the correct choice below and fill in the answer box within your choice.
?(Round to the nearest integer as? needed.)
A.
If 100 pregnant individuals were selected independently from this? population, we would expect
35


35 pregnancies to last less than 128


128 days.
Your answer is correct.
B.
If 100 pregnant individuals were selected independently from this? population, we would expect
nothing


pregnancies to last more than 128


128 days.
C.
If 100 pregnant individuals were selected independently from this? population, we would expect
nothing


pregnancies to last exactly 128


128 days.
?(b) Suppose a random sample of 19


19 pregnancies is obtained. Describe the sampling distribution of the sample mean length of pregnancies.
The sampling distribution of x overbar


x is normal
with mu Subscript x overbar


μxequals


=
131


131 and sigma Subscript x overbar


σxequals


=
nothing


.
?(Round to four decimal places as? needed.)