1. Week 3 – Multiple Choice
4) A random sample of 100 observations from a population with
standard deviation 60 yielded a sample mean of 111. Complete
parts a through c.
a) Test the null hypothesis that μ=100 against the alternative
hypothesis that μ>100, using α=0.05. Interpret the results of the
test.
⃝ Hₒ is not rejected
⃝ Hₒ is rejected
Interpret the results of the test. Choose the correct
interpretation below:
⃝ There is sufficient evidence to indicate the true population
mean is not equal to 100 at α=0.05
⃝ There is sufficient evidence to indicate the true population
mean is greater than 100 at α=0.05
⃝ There is sufficient evidence to indicate the true population
mean is smaller than 100 at α=0.05
b) Test the null hypothesis that μ=100 against the alternative
hypothesis that μ≠100, using α=0.05. Interpret the results of the
test.
⃝ Hₒ is not rejected
⃝ Hₒ is rejected
Interpret the results of the test. Choose the correct
interpretation below:
⃝ There is insufficient evidence to indicate μ is smaller than
100 at α=0.05
⃝ There is insufficient evidence to indicate μ is not equal to
100 at α=0.05
⃝ There is insufficient evidence to indicate μ is greater than
100 at α=0.05
c) Compare the results of the two test you conducted. Explain

2. why the results differ. Choose the correct answer below.
⃝ The results differ because the alternative hypothesis in part a
is more specific than the one in b
⃝ The results do not differ because these two tests are
equivalent
⃝ The results differ because the alternative hypothesis in part b
is more specific than the one in a
5) The final scores of games of a certain sport were compared
against the final point spreads established by oddmakers. The
difference between the game outcome and point spread (called
point-spread error) was calculated for 260 games. The mean and
standard deviation of the point-spread errors are x=1.2 and
s=11.4. Use this information to test the hypothesis that the true
mean point-spread error for all games differs from 0. Conduct
the test α=0.05 and interpret the result.
What is the appropriate conclusion at α=0.05?
⃝ A. Reject Hₒ. There is insufficient evidence to indicate that
μ≠0
⃝ B. Do not reject Hₒ. There is sufficient evidence to indicate
that μ≠0
⃝ C. Do not reject Hₒ. There is insufficient evidence to indicate
that μ≠0
⃝ D. Reject Hₒ. There is sufficient evidence to indicate that μ≠0
6) If a hypothesis test were conducted using α=0.01, for which
of the following p-values would the null hypothesis be rejected?
a. 0.009 b. 0.02
a) What is the conclusion for a p-value of 0.009?
⃝ A. Reject the null hypothesis since the p-value is not less
than the value α
⃝ B. Do not reject the null hypothesis since the p-value is less
than the value α
⃝ C. Do not reject the null hypothesis since the p-value is not
less than the value α
⃝ D. Reject the null hypothesis since the p-value is less than
the value α
b) What is the conclusion for a p-value of 0.02?

3. ⃝ A. Do not reject the null hypothesis since the p-value is not
less than the value α
⃝ B. Do not reject the null hypothesis since the p-value is less
than the value α
⃝ C. Reject the null hypothesis since the p-value is less than
the value α
⃝ D. Reject the null hypothesis since the p-value is not less
than the value α
7) For the α and observed significance level (p-value) pair,
indicate whether the null hypothesis would be rejected.
Α=0.01 p-value=0.45
Choose the correct conclusion below.
⃝ A. Do not reject the null hypothesis since the p-value is not
less than the value α
⃝ B. Reject the null hypothesis since the p-value is not less
than the value α
⃝ C. Reject the null hypothesis since the p-value is less than
the value α
⃝ D. Do not reject the null hypothesis since the p-value is less
than the value α
8) In a test of the hypothesis Hₒ: μ=10 versus μ≠10, a sample of
n=40 observations possessed mean x=10.7 and standard
deviation s=2.6. Find the p-value is p= _____________ (Round
to four decimal places as needed)
9) In a study it was found that the average age of cable TV
shoppers was 54 years. Suppose you want to test the null
hypothesis, Hₒ: μ=154, using a sample of n=80 cable TV
shoppers.
a) Find the p-value of a two-tailed test if x=55.1 and s=10.1
(Round to four decimal places as needed)
b) Find the p=value of an upper-tailed test if x=55.1 and
s=10.1(Round to four decimal places as needed)
10) A sample of six measurements, randomly selected from a
normally distributed population, resulted in the summary
statistics x=5.6 and s=1.2. Complete parts a through c
a) Test the null hypotheis that the mean of the population is 7

4. against the alternative hypothesis, μ<7. Use α=0.05.
⃝ A. Do not reject Hₒ. There is sufficient evidence to indicate
that μ<7
⃝ B. Reject Hₒ. There is sufficient evidence to indicate that μ<7
⃝ C. Do not reject Hₒ. There is insufficient evidence to indicate
that μ<7
⃝ D. Reject Hₒ. There is insufficient evidence to indicate that
μ<7
Test the null hypothesis that the mean of the population is 7
against the alternative hypothesis μ≠7. Use α=0.05.
⃝ A. Reject Hₒ. There is insufficient evidence to indicate that
μ≠7
⃝ B. Do not reject Hₒ. There is sufficient evidence to indicate
that μ≠7
⃝ D. Reject Hₒ. There is sufficient evidence to indicate that μ≠7
⃝ C. Do not reject Hₒ. There is insufficient evidence to indicate
that μ≠7
c)Find the observed significance level for each test.
Choose the correct significance level for part a below
⃝ A. p-value<0.0005
⃝ B. 0.050<p-value<0.100
⃝ D. 0.005<p-value<0.001
⃝ C. 0.005<p-value<0.010
⃝ E. 0.010<p-value<0.025
⃝ F. 0.001<p-value<0.005
Choose the correct significance level for part b below
⃝ A. 0.050<p-value<0.100
⃝ B. 0.100<p-value<0.200
⃝ D. p-value<0.001
⃝ C. 0.001<p-value<0.002
⃝ E. 0.020<p-value<0.050
⃝ F. 0.002<p-value<0.010

5. 11) Info below
a) Do the data indicate that the true mean number of suicide
bombings for all terrorist group attacks against this country
differs from 1.5? Use α=0.05 and Excel/DDXL printout to
answer the question
⃝ A. No. The data do not show that the true mean number of
suicide bombings differs from 1.5
⃝ B. Yes. The data show that the true mean number of suicide
bombings differs from 1.5
b) A 95% confidence interval for the mean μ, of the population
was found to be 1.85±0.510. Answer the question in part a
based on the 95% confidence interval
⃝ A. No. The data do not show that the true mean number of
suicide bombings differs from 1.5
⃝ B. Yes. The data show that the true mean number of suicide
bombings differs from 1.5
c) Do the inferences derived from the test (part a) and the
confidence interval (part b) agree? Explain why or why not.
⃝ A. They agree because both tests use the same value of α
⃝ B. They disagree because a hypothesis test is testing a
different event than the confidence interval test
⃝ C. They agree because both tests use the same data set
⃝ D. They disagree because the tests use a different value of α
d) What assumption(s) about the data must be true for the
inferences to be valid? Select all that apply.
⃝ A. The sample must be greater than 5% of the population
⃝ B. There cannot be any outliners
⃝ C. The population must be approximately normal
⃝ D. The sample must be less than 10% of the population
e) Use a graph to check whether the assumption(s) part d is
(are) reasonably satisfied. Comment on the validity of the
inference.
⃝ A. The assumption(s) seems (seem) reasonably satisfied
⃝ B. The assumption(s) does (do) not seem reasonably satisfied.
The data are not random.

6. ⃝ C. The assumption(s) does (do) not seem reasonably satisfied.
The data are skewed right.
⃝ D. The assumption(s) does (do) not seem reasonably
satisfied. The sample is small.
⃝ E. The assumption(s) does (do) not seem reasonably satisfied.
The data contain outliers.
12) When planning for a new forest road to be used for tree
harvesting, planners must select the location to minimize fractor
skidding distance. The skidding distances (in meters) were
measured at 20 randomly selected road sites. The data are given
below. A logger working on the road claims the mean skidding
distance is at least 412 meters. Is there sufficient evidence to
refute this claim? Use
450
355
440
280
431
490
400
205
578
544
386
296
185
265
273
399
308
312
137
430
Choose the correct answer below
⃝ A. Do not reject the claim. There is insufficient evidence to
indicate that μ<412 meters

7. ⃝ B. Reject the claim. There is sufficient evidence to indicate
that μ<412 meters
⃝ C. Do not reject the claim. There is sufficient evidence to
indicate that μ<412 meters
⃝ D. Reject the claim. There is insufficient evidence to indicate
that μ<412 meters
13) For he binomial sample sizes and null-hypothesized values
of p in each part, determine whether the sample size is large
enough to meet the required conditions for using the normal
approximation to conduct a valid large-sample hypothesis test
of the null hypothesis Hₒ: p=pₒ
Complete parts a through e
a) n=499,pₒ=0.05
⃝ A. The sample size is not large enough to use the normal
approximation
⃝ B. The sample size is large enough to use the normal
approximation
b) n=100,pₒ=0.99
⃝ A. The sample size is large enough to use the normal
approximation
⃝ B. The sample size is not large enough to use the normal
approximation
c) n=48,pₒ=0.2
⃝ A. The sample size is large enough to use the normal
approximation
⃝ B. The sample size is not large enough to use the normal
approximation
d) n=20,pₒ=0.2
⃝ A. The sample size is large enough to use the normal
approximation
⃝ B. The sample size is not large enough to use the normal
approximation
e) n=9,pₒ=0.4
⃝ A. The sample size is large enough to use the normal
approximation
⃝ B. The sample size is not large enough to use the normal

8. approximation
14) Suppose a consumer group rated 42 brands of toothpaste
based on whether or not the brand carries an American Dental
Association (ADA) seal verifying effective decay prevention.
The results of a hypothesis test for the proportion of brands
with the seal are shown to the right. Complete parts a through c
X
N
Sample p
P-value
21
42
0.500000
0.500
a) Give the null and alternative hypothesis for testing whether
the true proportion of toothpaste brands with the ADA seal
verifying effective decay prevention is less than 0.50.
⃝ A. Hₒ: p=0.50 vs Hₐ: p>0.50
⃝ B. Hₒ: p=0.50 vs Hₐ: p<0.50
⃝ C. Hₒ: p<0.50 vs Hₐ: p=0.50
⃝ D. Hₒ: p=0.50 vs Hₐ: p≠0.50
⃝ E. Hₒ: p≠0.50 vs Hₐ: p=0.50
⃝ F. c: p>0.50 vs Hₐ: p=0.50
b) Locate the p-value in the given table. The p-value is
_________. (Type an integer or a decimal)
c) Make the appropriate conclusion using α=0.10
⃝ A. Do not reject the null hypothesis since the p-value is not
less than the value α
⃝ B. Reject the null hypothesis since the p-value is not less
than the value α
⃝ C. Reject the null hypothesis since the p-value is less than
the value α
⃝ D. Do not reject the null hypothesis since the p-value is less

9. than the value α
15) In order to compare the means of two populations,
independent random samples of 385 observations are selected
from each population, with the results found in the table to the
right. Compare parts a through e
Sample 1
Sample 2
x₁ = 5,270
x₂ = 5,231
s₁ = 157
s₂ = 192
a) Use a 95% confidence interval to estimate the difference
between the population means (μ₁ -μ₂). Interpret the confidence
interval.
The confidence interval is (___,___)
Interpret the confidence interval. Select the correct answer from
the options below.
⃝ A. We are 95% confident that the difference between the
population means falls outside of the confidence interval
⃝ B. We are 95% confident that the difference between the
population means falls in the confidence interval
⃝ C. We are 95% confident that each of the population means is
contained in the confidence interval
⃝ D. We are 95% confident that each of the population means
falls outside of the confidence interval
b) Test the null hypothesis Hₒ:(μ₁ -μ₂) =0 versus the alternative
hypothesis Hₐ: (μ₁ -μ₂)≠0. Give the significance level of the
test, and interpret the result.
⃝ A. The p-value is approximately 0.0010, so we do not reject
Hₒ for α>0.0010
⃝ B. The p-value is approximately 0.0020, so we do not reject
Hₒ for α>0.0020
⃝ C. The p-value is approximately 0.0020, so we do not reject
Hₒ for α>0.0010

10. ⃝ D. The p-value is approximately 0.0010, so we reject Hₒ for
α>0.0010
⃝ E. The p-value is approximately 0.0020, so we reject Hₒ for
α>0.0020
⃝ F. The p-value is approximately 0.0020, so we reject Hₒ for
α>0.0010
c) Suppose the test in part b was conducted with the alternative
hypothesisHₐ:(μ₁ -μ₂)>0. How would your answer to part b
change?
⃝ A. The p-value would be 0.0020, so we would not reject Hₒ
for α>0.0020
⃝ B. The p-value would be 0.0010, so we wouldreject Hₒ for
α>0.0020
⃝ C. The p-value would be 0.0010, so we wouldreject Hₒ for
α>0.0010
⃝ D. The p-value would be 0.0010, so we would not reject Hₒ
for α>0.0010
⃝ E. The p-value would be 0.0020, so we would not reject Hₒ
for α>0.0010
⃝ F. The p-value would be 0.0020, so we wouldreject Hₒ for
α>0.0020
d) Test the null hypothesis Hₒ:(μ₁ -μ₂) =27 versus the alternative
hypothesis Hₐ: (μ₁ -μ₂)≠27. Give the significance level of the
test, and interpret the result.
⃝ A. The p-value is approximately 0.3424, so we do not reject
Hₒ for α≤0.3424
⃝ B. The p-value is approximately 0.1712, so we reject Hₒ for
α≤0.3424
⃝ C. The p-value is approximately 0.1712, so we do not reject
Hₒ for α≤0.1712
⃝ D. The p-value is approximately 0.1712, so reject Hₒ for
α≤1712
⃝ E. The p-value is approximately 0.3424, so reject Hₒ for
α≤0.3424

11. ⃝ F. The p-value is approximately 0.3424, so we reject Hₒ for
α≤0.1712
e) What assumptions are necessary to ensure the validity of the
inferential procedures applied in parts a-d?
⃝ A. We must assume that we have two dependent random
samples
⃝ B. We must assume that we have two independent random
samples
⃝ C. We must assume that the t-distribution should be used
⃝ D. We must assume that we have two small samples
16) To use the t-statistic to test for a diference between the
means of two populations, what assumptions must be made
about the two populations? About the two samples?
What assumption(s) must be made about the two populations?
Select all that apply.
⃝ A. Both populations must be selected independently of each
other
⃝ B. Both sampled populations must be approximately normally
distributed
⃝ C. There must be more than 30 samples selected from each
population
⃝ D. Both sampled populations must have approximately equal
population variances
What assumptions(s) must be made about the two samples?
Select all that apply
⃝ A. There must be more than 30 samples selected from each
population
⃝ B. The samples must be independent of each other
⃝ C. The samples must be normally distributed
17) Independent random samples from normal populations
produced the results shown in the table to the right. Complete
parts a through d
Sample 1
Sample 2
1.4

12. 2.8
3.3
3.3
2.9
3.5
2.9
3.8
3.3
a) Calculate the pooled estimate ơ²
s²p=____ (Round to four decimal places as needed)
b) Do the data provide sufficient evidence to indicate that
μ₂>μ₁? Test using α=0.10
⃝ No
⃝ Yes
c) Find a 90% confidence interval for (μ₁-μ₂).
The confidence interval is (___,___) (Round to two decimal
places as needed)
d) Which of the two inferential procedures, the test of
hypothesis in part b of the confidence interval in part c.
provides more information about (μ₁-μ₂)?
⃝The test of hypothesis in part b provides more information
about (μ₁-μ₂)
⃝Theconfidence interval in part c provides more information
about (μ₁-μ₂)
18) Independent random samples are selected from two
populations and are used to test the hypothesis Hₒ: (μ₁-μ₂)=0
against the alternative Hₐ:(μ₁-μ₂)≠0. An analysis of 233
observations from population 1 and 313 from population 2
yielded a p-value of 0.111. Complete parts a andb below.
a) Interpret the results of the computer analysis. Use
α≤0.10.
⃝ A. Since the given α value exceeds this p-value, there is
sufficient evidence to indicate that the population means are
different

13. ⃝ B. Since the p-value exceeds the given value of α, there is
insufficient evidence to indicate that the population means are
different
⃝ C. Since the given α ex value exceeds this p-value, there is
insufficient evidence to indicate that the population means are
different.
⃝ D. Since this p-value exceeds the given value of α, there is
sufficient evidence to indicate that the population means are
different
b) If the alternative hypothesis has been Hₐ:(μ₁-μ₂)<0, how
would the p-value change? Interpret the p-value for this one-
tailed test.
p-value = _______ (Type an integer or a decimal)
Interpret the p-value for this one-tailed test. Choose the correct
interpretation below.
⃝ A. Since the p-value for this one-tailed test exceeds the given
value of α, there is insufficient evidence to conclude that the
mean for population 1 is significantly lower than the mean for
population 2
⃝ B. Since the given value of α exceeds the p-value for this
one-tailed test, there is sufficient evidence to conclude that the
mean for population 1 is significantly lower than the mean for
population 2
⃝ C. There is not enough information to answer this question
19)
20)
21)
22)
23)

14. 24)
25
26)
Final
1)
2)
3)
4)
5)
6)

15. 7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
17)

16. 18)
19)
20)
21)
22)
23)
24)
25)

17. Week 5 Quiz
1)
2)
3)
4)
5)

18. 6)
7)
8)
9)
10)
11)
12)
13)

19. Week 4
Income Group
Sample Size
Mean Road Rage Score
Under $30,000
379
4.6
$30,000 to $60,000
392
5.08
Over $60,000
267
5.15
ANOVA results
F-value = 9.02
p-value <0.01
1) Researchers conduct a survey of a representative sample of
over 1,000 drivers. Based on how often each driver engaged in
road rage behavior, a road rage score was given. The drivers
were also grouped by annual income. The data were subjected to
an analysis of variance, with the results summarized in the
table.
Items in RED and underlinedare the multiple choices
Reject or Not Reject The null hypothesis that there is no
difference in mean road rage scores among variance income
classes because there is sufficient or insufficient evidence to
indicate a difference in mean road rage scores among various
income classes for a α≥0.01.

20. The information indicates that the road rage shows no
correlation,stays the same,increasesor decreasesas income
increases
2)
Group
1
1
1
1
1
1
2
2
2
2
2
2
2
2
3
3
3
3
4
4
4
4
4
4
4
Ethics response
2
2
1
4

21. 3
2
2
3
2
1
2
2
1
1
3
2
1
1
4
3
2
3
5
2
2
3)
4)

22. 5)
8)
9)
10)
11)
12)
13)
14)
15)
16)