In: Statistics and Probability
Suppose the lengths of the pregnancies of a certain animal are approximately normally distributed with mean
mu equals 135 daysμ=135 days
and standard deviation
sigma equals 14 daysσ=14 days.
Complete parts (a) through (f) below.Click here to view the standard normal distribution table (page 1).
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Click here to view the standard normal distribution table (page 2).
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(a) What is the probability that a randomly selected pregnancy lasts less than
130130
days?The probability that a randomly selected pregnancy lasts less than
130130
days is approximately
nothing.
(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
nothing
pregnancies to last more than
130130
days.
B.If 100 pregnant individuals were selected independently from this population, we would expect
nothing
pregnancies to last less than
130130
days.
C.If 100 pregnant individuals were selected independently from this population, we would expect
nothing
pregnancies to last exactly
130130
days.(b) Suppose a random sample of
1717
pregnancies is obtained. Describe the sampling distribution of the sample mean length of pregnancies.The sampling distribution of
x overbarx
is
▼
normal
skewed right
skewed left
with
mu Subscript x overbarμxequals=nothing
and
sigma Subscript x overbarσxequals=nothing.
(Round to four decimal places as needed.)
(c) What is the probability that a random sample of
1717
pregnancies has a mean gestation period of
130130
days or less?The probability that the mean of a random sample of
1717
pregnancies is less than
130130
days is approximately
nothing.
(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 independent random samples of size
nequals=1717
pregnancies were obtained from this population, we would expect
nothing
sample(s) to have a sample mean of exactly
130130
days.
B.If 100 independent random samples of size
nequals=1717
pregnancies were obtained from this population, we would expect
nothing
sample(s) to have a sample mean of
130130
days or less.
C.If 100 independent random samples of size
nequals=1717
pregnancies were obtained from this population, we would expect
nothing
sample(s) to have a sample mean of
130130
days or more.(d) What is the probability that a random sample of
5050
pregnancies has a mean gestation period of
130130
days or less?The probability that the mean of a random sample of
5050
pregnancies is less than
130130
days is approximately
nothing.
(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 independent random samples of size
nequals=5050
pregnancies were obtained from this population, we would expect
nothing
sample(s) to have a sample mean of exactly
130130
days.
B.If 100 independent random samples of size
nequals=5050
pregnancies were obtained from this population, we would expect
nothing
sample(s) to have a sample mean of
130130
days or less.
C.If 100 independent random samples of size
nequals=5050
pregnancies were obtained from this population, we would expect
nothing
sample(s) to have a sample mean of
130130
days or more.(e) What might you conclude if a random sample of
5050
pregnancies resulted in a mean gestation period of
130130
days or less?This result would be
▼
expected,
unusual,
so the sample likely came from a population whose mean gestation period is
▼
greater than
equal to
less than
135135
days.(f) What is the probability a random sample of size
1717
will have a mean gestation period within
1111
days of the mean?The probability that a random sample of size
1717
will have a mean gestation period within
1111
days of the mean is
nothing.
(Round to four decimal places as needed.)