Quiz 1 Stats Questions with Accurate Answers
(239.84, 248.16) correct answer The standard deviation of the weights of
elephants is known to be approximately 15 pounds. We wish to construct a 95%
confidence interval for the mean weight of newborn elephant calves. Fifty
newborn elephants are weighed. The sample mean is 244 pounds. The sample
standard deviation is 11 pounds.
Construct a 95% confidence interval for the population mean weight of newborn
elephants. State the confidence interval. (Round your answers to two decimal
places.)
(a) lower limit = 0.72
(b) upper limit = 0.88
(c) error bound = 0.08 correct answer The Ice Chalet offers dozens of different
beginning ice-skating classes. All of the class names are put into a bucket. The 5
P.M., Monday night, ages 8 to 12, beginning ice-skating class was picked. In that
class were 64 girls and 16 boys. Suppose that we are interested in the true
proportion of girls, ages 8 to 12, in all beginning ice-skating classes at the Ice
Chalet. Assume that the children in the selected class are a random sample of the
population.
Construct a 92% Confidence Interval for the true proportion of girls in the ages 8
to 12 beginning ice-skating classes at the Ice Chalet.
Calculate the following. (Round your answers to two decimal places.)
(a) lower limit
(b) upper limit
,(c) error bound
(a) lower limit: 2.93
(b) upper limit: 3.59
(c) error bound: 0.33 correct answer The data in the table below are the result of
a random survey of 39 national flags (with replacement between picks) from
various countries. We are interested in finding a confidence interval for the true
mean number of colors on a national flag. Let X = the number of colors on a
national flag.
X Freq.
11
27
3 18
47
56
Construct a 95% confidence interval for the true mean number of colors on
national flags.
Calculate the following. (Round your answers to two decimal places.)
(a) lower limit
(b) upper limit
(c) error bound
(a) null hypothesis
H0: p = 0.095
, (b) alternative hypothesis
Ha: p < 0.095 correct answer The National Institute of Mental Health published an
article stating that in any one-year period, approximately 9.5 percent of American
adults suffer from depression or a depressive illness. Suppose that in a survey of
100 people in a certain town, seven of them suffered from depression or a
depressive illness. If you were conducting a hypothesis test to determine if the
true proportion of people in that town suffering from depression or a depressive
illness is lower than the percent in the general adult American population, what
would the null and alternative hypotheses be?
(i) Decision: reject the null hypothesis
(ii) Reason for the decision: Since α > p-value, we reject the null hypothesis.
(iii) Conclusion (write out in a complete sentence): There is sufficient evidence to
conclude that the mean length of time on death row is not 15 years. correct
answer A random survey of 75 death row inmates revealed that the mean length
of time on death row is 17.7 years with a standard deviation of 6.7 years. Conduct
a hypothesis test to determine if the population mean time on death row could
likely be 15 years.
At a pre-conceived
α = 0.05,
what do you determine for each of the following?
(i) Decision:
(ii) Reason for the decision:
(iii) Conclusion (write out in a complete sentence):
0
0
(239.84, 248.16) correct answer The standard deviation of the weights of
elephants is known to be approximately 15 pounds. We wish to construct a 95%
confidence interval for the mean weight of newborn elephant calves. Fifty
newborn elephants are weighed. The sample mean is 244 pounds. The sample
standard deviation is 11 pounds.
Construct a 95% confidence interval for the population mean weight of newborn
elephants. State the confidence interval. (Round your answers to two decimal
places.)
(a) lower limit = 0.72
(b) upper limit = 0.88
(c) error bound = 0.08 correct answer The Ice Chalet offers dozens of different
beginning ice-skating classes. All of the class names are put into a bucket. The 5
P.M., Monday night, ages 8 to 12, beginning ice-skating class was picked. In that
class were 64 girls and 16 boys. Suppose that we are interested in the true
proportion of girls, ages 8 to 12, in all beginning ice-skating classes at the Ice
Chalet. Assume that the children in the selected class are a random sample of the
population.
Construct a 92% Confidence Interval for the true proportion of girls in the ages 8
to 12 beginning ice-skating classes at the Ice Chalet.
Calculate the following. (Round your answers to two decimal places.)
(a) lower limit
(b) upper limit
,(c) error bound
(a) lower limit: 2.93
(b) upper limit: 3.59
(c) error bound: 0.33 correct answer The data in the table below are the result of
a random survey of 39 national flags (with replacement between picks) from
various countries. We are interested in finding a confidence interval for the true
mean number of colors on a national flag. Let X = the number of colors on a
national flag.
X Freq.
11
27
3 18
47
56
Construct a 95% confidence interval for the true mean number of colors on
national flags.
Calculate the following. (Round your answers to two decimal places.)
(a) lower limit
(b) upper limit
(c) error bound
(a) null hypothesis
H0: p = 0.095
, (b) alternative hypothesis
Ha: p < 0.095 correct answer The National Institute of Mental Health published an
article stating that in any one-year period, approximately 9.5 percent of American
adults suffer from depression or a depressive illness. Suppose that in a survey of
100 people in a certain town, seven of them suffered from depression or a
depressive illness. If you were conducting a hypothesis test to determine if the
true proportion of people in that town suffering from depression or a depressive
illness is lower than the percent in the general adult American population, what
would the null and alternative hypotheses be?
(i) Decision: reject the null hypothesis
(ii) Reason for the decision: Since α > p-value, we reject the null hypothesis.
(iii) Conclusion (write out in a complete sentence): There is sufficient evidence to
conclude that the mean length of time on death row is not 15 years. correct
answer A random survey of 75 death row inmates revealed that the mean length
of time on death row is 17.7 years with a standard deviation of 6.7 years. Conduct
a hypothesis test to determine if the population mean time on death row could
likely be 15 years.
At a pre-conceived
α = 0.05,
what do you determine for each of the following?
(i) Decision:
(ii) Reason for the decision:
(iii) Conclusion (write out in a complete sentence):
0
0
