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Copyright © 2014 Edmentum - All rights reserved.
AP Statistic Blizzard Bag 2014 - 2015 Statistical Inference
1. Which of the following will increase the power of a hypothesis test?
I)
increasing the sample size, n, used in the test
II) increasing the significance level,
, used in the test
III) increasing the probability of a type II error,
, in the test
IV) decreasing the sample size, n, used in the test
V) decreasing the significance level,
used in the test
A. Statements II and IV
B. Statement III only
C. Statements IV and V
D. Statements I and II
E. Statements I and V
2. Determine if the following situation would result in a two-tailed test, a left-tailed test, or a
right-tailed test.
A pharmaceutical company wants to test whether the effects of a new medicine are different for
men and women.
A. The situation results in a right-tailed test.
B. The situation results in a two-tailed test.
C. The situation results in a left-tailed test.
D. There is not enough information to determine the resulting test of the situation.
E. The situation can result in a left-tailed test or a right-tailed test.
3. The sample mean, , is a point estimate of the population mean, , given that which of the
following statements is true?
A. The sample mean, , is always the point estimate of the population mean, .
B. The sample mean,
, can never be the point estimate of the population mean,
.
C. The sample size, n, is equal to the size of the population.
D. The sample size, n, is large enough to accurately represent the population.
E. The sample represents a proportion of the population.
4. The sample proportion, is a point estimate of the population proportion, , given that
which of the following statements is true?
A. The sample proportion,
proportion, .
, is always a point estimate of the population
B. The sample proportion,
, is biased.
C. The sample proportion,
proportion, .
, is never a point estimate of the population
D. The sample proportion,
, is unbiased.
E. The sample represents a proportion of the population.
5. Kendra wants to know the average height of the 30,000 ninth grade students in Florida. She
randomly selects 1,000 ninth graders in Florida, assuring that the group accurately represents
all ninth grade students in Florida. Kendra finds their average height to be65 inches. What
assumption can be made regarding the approximate average height of all ninth grade students
in Florida?
A. The approximate average height of ninth grade students in Florida is greater
than65 inches.
B. The approximate average height of ninth grade students in Florida is 65 inches.
C. No assumptions can be made regarding the average height of ninth grade students
in Florida because the sample size is too small.
D. The approximate average height of ninth grade students in Florida is less than65
inches.
6. International Business Computers, IBC, claims that 85% of their total customers are satisfied
with their customer support program. To test this claim, a technology critic randomly selected
250 IBC customers and surveyed them. Among the sampled IBC customers, only 78% said they
are satisfied with the customer support program. Using a 5% significance level, should the critic
reject IBC's claim that 85% of their customers are satisfied with their customer support program
and why?
A. The null hypothesis is failed to be rejected because the P-value of 0.0024 is greater
than the significance level; therefore, the critic fails to reject IBC's claim.
B. The null hypothesis is rejected because the P-value of 0.0012 is less than the
significance level; therefore, the critic rejects IBC's claim.
C. The null hypothesis is failed to be rejected because the P-value of 0.0024 is less
than the significance level; therefore, the critic fails to reject IBC's claim.
D. The null hypothesis is rejected because the P-value of 0.0024 is greater than the
significance level; therefore, the critic rejects IBC's claim.
E. The null hypothesis is rejected because the P-value of 0.0024 is less than the
significance level; therefore, the critic rejects IBC's claim.
7. Andrew went on a road trip. The number of hours driven, x, and the distance traveled, y, are
shown in the table below.
Distance Traveled over Time
x
y
(hours) (miles)
1
50
2
110
3
150
4
220
5
275
Construct a 95% confidence interval for the slope of the least-squares regression line for the
data above.
A.
B.
C.
D.
E.
8. Washington Heights High School claims that the mean IQ of their students is 110. An
educational research group wants to test this claim. The group randomly selected 20 students
from Washington Heights High School and found the mean IQ of the sample to be 100 with a
standard deviation of 15. Using a 1% significance level, should the educational research group
reject the school's claim that the mean IQ of their students is equal to 110 and why?
A. The null hypothesis is rejected because the P-value of 0.0075 is less than the
significance level; therefore, the educational research group rejects the school's
claim regarding the mean IQ of their students.
B. The null hypothesis is rejected because the P-value of 0.00375 is less than the
significance level; therefore, the educational research group rejects the school's
claim regarding the mean IQ of their students.
C. The null hypothesis is failed to be rejected because the P-value of 0.0075 is less
than the significance level; therefore, the educational research group fails to reject
the school's claim regarding the mean IQ of their students.
D. The null hypothesis is failed to be rejected because the P-value of 0.0075 is greater
than the significance level; therefore, the educational research group fails to reject
the school's claim regarding the mean IQ of their students.
E. The null hypothesis is rejected because the P-value of 0.0075 is greater than the
significance level; therefore, the educational research group rejects the school's
claim regarding the mean IQ of their students.
9. A grocery store wants to know the mean purchase price per customer. The store randomly
selected 455 customers and found their mean purchase price to be $34.00. The store also
found that the standard deviation of the sample to be $10.00. What is the 95% confidence
interval for the mean purchase price per customer?
A.
B.
C.
D.
E.
10. A kinesiologist is conducting a study regarding the running times of men and women. The
kinesiologist randomly selected 620 women and found their average running time per mile to
be 8.5 minutes. He also found the standard deviation of the female sample to be 2 minutes. The
kinesiologist then randomly selected 680 men and found their average running time per mile to
be 6.5 minutes. He also found the standard deviation of the male sample to be 4 minutes.
Construct a 99% confidence interval for the difference between the mean running times of
women and men.
A.
B.
C.
D.
E.
11. An automotive insurance company conducted a survey regarding teenagers and dangerous
driving habits. The company surveyed 758 teenagers and found that 52% of the surveyed
teenagers text while driving. What is the 99% confidence interval for the proportion of
teenagers that text while driving?
A.
B.
C.
D.
E.
12. Which of the following is the best description of the two types of statistical hypotheses?
A. The null hypothesis (H0) is a claim about a population parameter that is assumed to
be true until proven false. The alternative hypothesis (HA) is a claim about a
population parameter that is only true if the null hypothesis is false.
B. The null hypothesis (H0) is a claim about a population parameter that is assumed to
be false until proven true. The alternative hypothesis (HA) is a claim about a
population parameter that is only true if the null hypothesis is false.
C. The null hypothesis (H0) is a claim about a population parameter c that is assumed
to be true until proven false. The alternative hypothesis (HA) is a claim about a
population parameter that is only true if the null hypothesis is false.
D. The alternative hypothesis (HA) is a claim about a population parameter that is
assumed to be true until proven false. The null hypothesis (H0) is a claim about a
population parameter that is only true if the null hypothesis is false.
E. A Type I error, |latex("\alpha")|, occurs when a true null hypothesis is rejected. A
Type II error, |latex("\beta")|, occurs when a false null hypothesis is not rejected.
13. Which of the following statements are true regarding P-values?
I)
The P-value is the probability that the null hypothesis is true.
II) The P-value is the probability of the observed statistic given that the null hypothesis is
true.
III) If the P-value is less than the significance level,
, then the null hypothesis is rejected.
IV) If the P-value is less than the significance level,
hypothesis.
, then there is a failure to reject the null
A. Statements I and IV
B. Statements II and III
C. Statements I and III
D. Statements II and IV
E. Statement I only
14. Quick View is an internet service provider. According to the company's records, the average
daily internet usage per household in 2005 was 30 minutes per day. In 2009, the company
claimed that the mean daily internet usage per household had changed. To test this claim, a
customer randomly selected 100 households. The mean daily internet usage per sampled
household was 37 minutes with a standard deviation of 20 minutes. Using a 5% significance
level, should the customer reject Quick View's claim regarding the change in the mean daily
internet usage per household and why?
A. The null hypothesis is rejected because the P-value of 0.0004 is greater than the
significance level; therefore, the customer fails to reject Quick View's claim
regarding the change in the mean daily internet usage per household.
B. The null hypothesis is failed to be rejected because the P-value of 0.0004 is less
than the significance level; therefore, the customer rejects Quick View's claim
regarding the change in the mean daily internet usage per household.
C. The null hypothesis is failed to be rejected because the P-value of 0.0004 is greater
than the significance level; therefore, the customer rejects Quick View's claim
regarding the change in the mean daily internet usage per household.
D. The null hypothesis is rejected because the P-value of 0.0004 is less than the
significance level; therefore, the customer fails to reject Quick View's claim
regarding the change in the mean daily internet usage per household.
E. The null hypothesis is failed to be rejected because the P-value of 0.0002 is less
than the significance level; therefore, the customer rejects Quick View's claim
regarding the change in the mean daily internet usage per household.
15. Sweets Candy Company produces large bags of assorted candy. Each bag contains 200
pieces of candy. The company claims that 20% of the candy in each bag are pieces of gum, 40%
of the candy in each bag are lollipops, and 40% of the candy in each bag are peppermint pieces.
To test this claim, Matthew purchased one bag of Sweet's candy. The bag contained 60 pieces
of gum, 80 lollipops, and 60 peppermint pieces. Using a 1% significance level, should Matthew
reject the candy company's claim?
A. The null hypothesis is rejected because the P-value of 0.0005 is less than the
significance level; therefore, Matthew rejects the candy company's claim.
B. The null hypothesis is rejected because the P-value of 0.0005 is greater than the
significance level; therefore, Matthew rejects the candy company's claim.
C. The null hypothesis is failed to be rejected because the P-value of 0.9995 is greater
than the significance level; therefore, Matthew fails to reject the candy company's
claim.
D. The null hypothesis is failed to be rejected because the P-value of 0.0005 is less
than the significance level; therefore, Matthew fails to rejects the candy company's
claim.
E. The null hypothesis is failed to be rejected because the P-value of 0.0005 is greater
than the significance level; therefore, Matthew fails to rejects the candy company's
claim.