CS 2206 Questions 1-40 Answers
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Question
1 of 40
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2.5 Points
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A
psychologist claims that more than 29 percent of the professional population
suffers from problems due to extreme shyness. Assuming that a hypothesis test
of the claim has been conducted and that the conclusion is failure to reject
the null hypothesis, state the conclusion in non-technical terms.
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A.
There is sufficient evidence to support the claim that the true proportion is
less than 29 percent.
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B.
There is not sufficient evidence to support the claim that the true
proportion is greater than 29 percent.
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C.
There is sufficient evidence to support the claim that the true proportion is
equal to 29 percent.
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D.
There is sufficient evidence to support the claim that the true proportion is
greater than 29 percent.
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Question
2 of 40
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2.5 Points
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A
study of a brand of “in the shell peanuts” gives the following results:
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A
significant event at the 0.01 level is a fan getting a bag with how many
peanuts?
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A.
30 peanuts
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B.
25 or 30 peanuts
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C.
25 or 55 peanuts
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D.
25 peanuts
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Question
3 of 40
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2.5 Points
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without
computing a P-value, determine whether the alternate hypothesis is supported
and give a reason for your conclusion.
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A.
is
less than 1 standard deviation above the claimed mean.
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B.
is
more than 4 standard deviations above the claimed mean.
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C.
is
less than 1 standard deviation above the claimed mean.
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D.
is
more than 4 standard deviations above the claimed mean.
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Question
4 of 40
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2.5 Points
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A
two-tailed test is conducted at the 0.10 significance level. What is the
P-value required to reject the null hypothesis?
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A.
Greater than or equal to .010
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B.
Greater than or equal to 0.05
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C.
Less than or equal to 0.10
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D.
Less than or equal to 0.05
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Question
5 of 40
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2.5 Points
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In
1990, the average duration of long-distance telephone calls originating in one
town was 9.3 minutes. A long-distance telephone company wants to perform a
hypothesis test to determine whether the average duration of long-distance
phone calls has changed from the 1990 mean of 9.3 minutes. Formulate the null
and alternative hypotheses for the study described.
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A.
Ho: µ = 9.3
minutes H a : µ < 9.3
minutes
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B.
Ho: µ = 9.3
minutes H a : µ > 9.3
minutes
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C.
Ho: µ = 9.3
minutes H a : µ ¹ 9.3 minutes
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D.
Ho: µ ¹ 9.3 minutes H a : µ = 9.3 minutes
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Question
6 of 40
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2.5 Points
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At
one school, the mean amount of time that tenth-graders spend watching
television each week is 18.4 hours. The principal introduces a campaign to
encourage the students to watch less television. One year later, the principal
wants to perform a hypothesis test to determine whether the average amount of
time spent watching television per week has decreased.
Formulate the null and alternative hypotheses for the study described.
Formulate the null and alternative hypotheses for the study described.
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A.
Ho: µ = 18.4
hours H a : µ ¹ 18.4 hours
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B.
Ho: µ = 18.4
hours H a : µ < 18.4
hours
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C.
Ho: µ ³ 18.4 hours H a : µ < 18.4 hours
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D.
Ho: µ = 18.4
hours H a : µ > 18.4
hours
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Question
7 of 40
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2.5 Points
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The
owner of a football team claims that the average attendance at home games is
over 4000, and he is therefore justified in moving the team to a city with a
larger stadium. Assume that a hypothesis test of the claim has been conducted
and that the conclusion of the test was to reject the null hypothesis. Identify
the population to which the results of the test apply.
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A.
All games played by the team in question in which the attendance is over 4000
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B.
All future home games to be played by the team in question
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C.
All home games played by the team in question
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D.
None of the populations given are appropriate
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Question
8 of 40
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2.5 Points
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A
long-distance telephone company claims that the mean duration of long-distance
telephone calls originating in one town was greater than 9.4 minutes, which is
the average for the state. Determine the conclusion of the hypothesis test
assuming that the results of the sampling do not lead to rejection of the null
hypothesis.
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A.
Conclusion: Support the claim that the mean is less than 9.4 minutes.
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B.
Conclusion: Support the claim that the mean is greater than 9.4 minutes.
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C.
Conclusion: Support the claim that the mean is equal to 9.4 minutes.
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D.
Conclusion: Do not support the claim that the mean is greater than 9.4
minutes.
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Question
9 of 40
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2.5 Points
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A
consumer group claims that the mean running time for a certain type of
flashlight battery is not the same as the manufacturer’s claims. Determine the
null and alternative hypotheses for the test described.
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A.
H0: µ = Manufacturer’s
claims Ha: µ < Manufacturer’s
claims
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B.
H0: µ = Manufacturer’s
claims Ha: µ ¹ Manufacturer’s claims
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C.
H0: µ = Manufacturer’s claims Ha:
µ > Manufacturer’s claims
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D.
H0: µ ¹ Manufacturer’s claims Ha:
µ = Manufacturer’s claims
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Question
10 of 40
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2.5 Points
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In
the past, the mean running time for a certain type of flashlight battery has
been 8.0 hours. The manufacturer has introduced a change in the production
method and wants to perform a hypothesis test to determine whether the mean
running time has increased as a result. The hypotheses are:
H0 : µ = 8.0 hours
Ha : µ > 8.0 hours
Explain
the meaning of a Type II error.
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A.
Concluding that µ > 8.0 hours when in fact µ > 8.0 hours
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B.
Failing to reject the hypothesis that µ = 8.0 hours when in fact µ >
8.0 hours |
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C.
Concluding that µ > 8.0 hours
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D.
Failing to reject the hypothesis that µ = 8.0 hours when in fact µ = 8.0
hours
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Question
11 of 40
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2.5 Points
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The
principal of a middle school claims that annual incomes of the families of the
seventh-graders at his school vary more than the annual incomes of the families
of the seventh-graders at a neighboring school, which have variation described
by s = $13,700.
Assume that a hypothesis test of the claim has been conducted and that the
conclusion of the test was to reject the null hypothesis. Identify the
population to which the results of the test apply.
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A.
The current seventh graders at the principal’s school
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B.
Seventh graders’ families at the school with a standard deviation of $13,700
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C.
All of the families of the class of seventh graders at the principal’s school
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D.
All seventh graders’ families
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Question
12 of 40
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2.5 Points
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If
a fan purchased a bag with 30 peanuts, what is the lowest level at which this
would be a significant event?
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A.
0.05
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B.
0.025
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C.
0.01
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D.
It is not significant at any of the levels given
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Question
13 of 40
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2.5 Points
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In
1990, the average duration of long-distance telephone calls originating in one
town was 9.4 minutes. A long-distance telephone company wants to perform a
hypothesis test to determine whether the average duration of long-distance
phone calls has changed from the 1990 mean of 9.4 minutes. The mean duration
for a random sample of 50 calls originating in the town was 8.6 minutes. Does
the data provide sufficient evidence to conclude that the mean call duration,
µ, is different from the 1990 mean of 9.4 minutes? Perform the appropriate
hypothesis test using a significance level of 0.01. Assume thats = 4.8 minutes.
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A.
With a z of -1.2 there is sufficient evidence to conclude that the mean
value has changed from the 1990 mean of 9.4 minutes. |
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B.
With a P-value of 0.2302 there is not sufficient evidence to conclude
that the mean value is less than the 1990 mean of 9.4 minutes. |
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C.
With a P-value of 0.2302 there is sufficient evidence to conclude that
the mean value is less than the 1990 mean of 9.4 minutes. |
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D.
With a z of –1.2 there is not sufficient evidence to conclude that the
mean value has changed from the 1990 mean of 9.4 minutes. |
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Question
14 of 40
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2.5 Points
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A
researcher wants to check the claim that convicted burglars spend an average of
18.7 months in jail. She takes a random sample of 35 such cases from court
files and finds that months. Assume that the population standard
deviation is 7 months. Test the null hypothesis that µ = 18.7 at the 0.05
significance level.
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A.
Do
not reject the null hypothesis and conclude that the claim that the mean is
different from 18.7 months is supported.
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B.
Do
not reject the null hypothesis and conclude that the claim that the mean is
different from 18.7 months cannot be supported.
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C.
Reject
the null hypothesis and conclude that the claim that the mean is different
from 18.7 months is supported.
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D.
Reject
the null hypothesis and conclude that the claim that the mean is different
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Question
15 of 40
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2.5 Points
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The
owner of a football team claims that the average attendance at home games is
over 3000, and he is therefore justified in moving the team to a city with a
larger stadium. Assuming that a hypothesis test of the claim has been conducted
and that the conclusion is failure to reject the null hypothesis, state the
conclusion in non-technical terms.
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A.
There is sufficient evidence to support the claim that the mean attendance is
greater than 3000.
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B.
There is sufficient evidence to support the claim that the mean attendance is
equal to 3000.
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C.
There is not sufficient evidence to support the claim that the mean
attendance is greater than 3000.
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D.
There is not sufficient evidence to support the claim that the mean
attendance is less than 3000.
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Question
16 of 40
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2.5 Points
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A
two-tailed test is conducted at the 5% significance level. Which of the
z-scores below is the smallest one that leads to rejection of the null
hypothesis?
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A.
1.12
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B.
1.48
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C.
1.84
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D.
2.15
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Question
17 of 40
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2.5 Points
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A
consumer advocacy group claims that the mean amount of juice in a 16
ounce bottled drink is not 16 ounces, as stated by the bottler.
Determine the null and alternative hypotheses for the test described.
ounce bottled drink is not 16 ounces, as stated by the bottler.
Determine the null and alternative hypotheses for the test described.
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A.
H0: µ = 16
ounces Ha: µ < 16 ounces
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B.
H0: µ ¹ 16 ounces Ha: µ
= 16 ounces
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C.
H0: µ = 16 ounces Ha:
µ > 16 ounces
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D.
H0: µ = 16
ounces Ha:
µ ¹ 16 ounces
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Question
18 of 40
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2.5 Points
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A
two-tailed test is conducted at the 5% significance level. What is the left
tail percentile required to reject the null hypothesis?
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A.
97.5%
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B.
5%
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C.
2.5%
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D.
95%
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Question
19 of 40
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2.5 Points
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A
poll of 1,068 adult Americans reveals that 52% of the voters surveyed prefer
the Democratic candidate for the presidency. At the 0.05 significance level,
test the claim that more than half of all voters prefer the Democrat.
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A.
Reject the null hypothesis. Conclude that there is insufficient evidence that
more than half of all voters prefer Democrats.
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B.
Do not reject the null hypothesis. Conclude that there is sufficient evidence
that more than half of all voters prefer Democrats.
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C.
Reject the null hypothesis. Conclude that there is sufficient evidence that
more than half of all voters prefer Democrats.
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D.
Do not reject the null hypothesis. Conclude that there is insufficient
evidence that more than half of all voters prefer Democrats.
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Question
20 of 40
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2.5 Points
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A
skeptical paranormal researcher claims that the proportion of Americans that
have seen a UFO is less than 1 in every one thousand. State the null hypothesis
and the alternative hypothesis for a test of significance.
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A.
H0: p =
0.001 Ha: p > 0.001
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B.
H0: p =
0.001 Ha:
p < 0.001
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C.
H0: p >
0.001 Ha: p = 0.001
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D.
H0: p <
0.001 Ha: p = 0.001
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Question
21 of 40
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2.5 Points
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Which
of the following statements is true?
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A.
The p distribution cannot be used when finding a confidence interval for the
population mean with a small sample anytime the population standard deviation
is unknown.
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B.
The t distribution can be used when finding a confidence interval for the
population mean with a small sample anytime the population standard deviation
is unknown.
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C.
The t distribution cannot be used when finding a confidence interval for the
population mean with a small sample anytime the population standard deviation
is unknown.
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D.
The p distribution can be used when finding a confidence interval for the
population mean with a small sample anytime the population standard deviation
is unknown
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Question
22 of 40
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2.5 Points
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One
hundred people are selected at random and tested for colorblindness to
determine whether gender and colorblindness are independent. The following
counts were observed.
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Colorblind
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Not Colorblind
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Total
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Male
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7
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53
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60
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Female
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1
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39
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40
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Total
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8
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92
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100
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Find
the value of the X2 statistic for the data above.
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A.
1.325
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B.
1.318
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C.
1.286
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D.
1.264
None of the options are true. The
Chi-square test statistic is 2.740.
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Question
23 of 40
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2.5 Points
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The
margin of error in estimating the population mean of a normal population is E =
9.3 when the sample size is 15. If the sample size had been 18 and the sample
standard deviation did not change, would the margin of error be larger or
smaller than 9.3? Explain your answer.
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A.
Smaller. E decreases as the square root of the sample size gets larger.
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B.
Smaller. E increases as the square root of the sample size gets larger.
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C.
Larger. E decreases as the square root of the sample size gets larger.
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D.
Larger. E increases as the square root of the sample size gets larger.
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Question
24 of 40
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2.5 Points
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The
__________ test statistic is for the one-way analysis of variance.
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A.
P-Value
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B.
t
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C.
F
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D.
p
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Question
25 of 40
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2.5 Points
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A
95% confidence interval for the mean of a normal population is found to be 15.6
< µ < 25.2. What is the margin of error?
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A.
3.9
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B.
4.8
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C.
4.9
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D.
3.7
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Question
26 of 40
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2.5 Points
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A
golfer wished to find a ball that would travel more than 180 yards when hit
with his 5-iron with a club speed of 90 miles per hour. He had a golf equipment
lab test a low compression ball by having a robot swing his club 7 times at the
required speed.
Data
from this test resulted in a sample mean of 184.2 yards and a sample standard
deviation of 5.8 yards. Assuming normality, carry out a hypothesis test at the
0.05 significance level to determine whether the ball meets the golfer’s
requirements. Use the partial t-table below.
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Area in one tail
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0.025
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0.05
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Area in two tails
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Degrees of
Freedom n – 1 |
0.05
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0.10
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6
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2.447
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1.943
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7
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2.365
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1.895
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8
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2.306
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1.860
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9
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2.262
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1.833
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A.
Reject
the null hypothesis. The data do not provide sufficient evidence that the
average distance is greater than 180 yards.
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B.
Reject the null hypothesis. The data do provide sufficient evidence that the
average distance is greater than 180 yards.
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C.
Do not reject the null hypothesis. The data do provide sufficient evidence
that the average distance is greater than 180 yards.
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D.
Do not reject the null hypothesis. The data do not provide sufficient
evidence that the average distance is greater than 180 yards.
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Question
29 of 40
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2.5 Points
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One
hundred people are selected at random and tested for colorblindness to
determine whether gender and colorblindness are independent. The following
counts were observed.
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Colorblind
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Not Colorblind
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Total
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Male
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8
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52
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60
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Female
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2
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38
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40
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Total
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10
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90
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100
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If
gender and colorblindness are independent, find the expected values
corresponding to the four combinations of gender and colorblindness, and enter
them in the following table along with row and column totals.
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Colorblind
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Not Colorblind
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Total
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Male
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Female
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Total
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A.
Male Colorblind 6.0; Male Not Colorblind 54.0
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B.
Male Colorblind 7.0; Male Not Colorblind 53.0
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C.
Male Colorblind 8.0; Male Not Colorblind 52.0
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D.
Male Colorblind 6.0; Male Not Colorblind 53.0
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Question
30 of 40
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2.5 Points
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The
margin of error in estimating the population mean of a normal population is E =
9.3 when the sample size is 15. If the sample size had been 25 and the sample
standard deviation did not change, would the margin of error be larger or
smaller than 9.3?
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A.
Smaller. E increases as the square root of the sample size gets larger.
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B.
Smaller. E decreases as the square root of the sample size gets larger.
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C.
Larger. E decreases as the square root of the sample size gets larger.
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D.
Larger. E increases as the square root of the sample size gets larger.
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Question
31 of 40
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2.5 Points
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A
golfer wished to find a ball that would travel more than 180 yards when hit
with his 5-iron with a club speed of 90 miles per hour. He had a golf equipment
lab test a low compression ball by having a robot swing his club 7 times at the
required speed. State the null and alternative hypotheses for this test.
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A.
H0:
µ = 180; Ha: µ > 180
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B.
H0:
µ > 180; Ha: µ > 180
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C.
H0:
µ < 180; Ha: µ > 180
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D.
H0:
µ = 180; Ha: µ < 180
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Question
32 of 40
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2.5 Points
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A
95% confidence interval for the mean of a normal population is found to be 17.6
< µ < 23.6. What is the margin of error?
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A.
2.0
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B.
2.7
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C.
3.0
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D.
4.0
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Question
34 of 40
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2.5 Points
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Which
of the following statements is true?
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A.
The t distribution cannot be used when finding a confidence interval for the
population mean with a small sample whenever the sample comes from a
symmetric population.
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B.
The t distribution can be used when finding a confidence interval for the
population mean with a small sample whenever the sample comes from a
symmetric population.
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C.
The p distribution can be used when finding a confidence interval for the
population mean with a small sample whenever the sample comes from a
symmetric population.
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D.
The p distribution can be used when finding a confidence interval for the
population mean with a small sample whenever the sample comes from a
symmetric population
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Question
35 of 40
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2.5 Points
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The
following data were analyzed using one-way analysis of variance.
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A
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B
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C
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34
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27
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19
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26
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23
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21
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31
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29
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22
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28
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21
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12
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Which
one of the following statements is correct?
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A.
The purpose of the analysis is to determine whether the groups A, B, and C
are independent.
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B.
The purpose of the analysis is to test the hypothesis that the population
means of the three groups are equal.
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C.
The purpose of the analysis is to test the hypothesis that the population
variances of the three groups are equal.
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D.
The purpose of the analysis is to test the hypothesis that the sample means
of the three groups are equal.
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Question
36 of 40
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2.5 Points
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The
following data were analyzed using one-way analysis of variance.
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A
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B
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C
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34
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27
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19
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26
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23
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31
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31
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29
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22
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28
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21
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22
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Which
one of the following statements is correct?
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A.
The
purpose of the analysis is to determine whether the groups A, B, and C are
independent.
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B.
The purpose of the analysis is to test the hypothesis that the population
means of the three groups are equal.
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C.
The purpose of the analysis is to test the hypothesis that the population variances
of the three groups are equal.
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D.
The purpose of the analysis is to test the hypothesis that the sample means
of the three groups are equal.
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Question
37 of 40
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2.5 Points
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A
golfer wished to find a ball that would travel more than 160 yards when hit
with his 7-iron with a club speed of 90 miles per hour. He had a golf equipment
lab test a low compression ball by having a robot swing his club 8 times at the
required speed.
Data
from this test resulted in a sample mean of 163.2 yards with a sample
standard deviation of 5.8 yards. Assuming normality, carry out a hypothesis
test at the 0.05 significance level to determine whether the ball meets the
golfer’s requirements. Use the partial t-table below to solve this problem.
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Area in one tail
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0.025
|
0.05
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Area in two tails
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Degrees of
Freedom n - 1 |
0.05
|
0.10
|
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6
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2.447
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1.943
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7
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2.365
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1.895
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8
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2.306
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1.860
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9
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2.262
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1.833
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A.
Do
not reject the null hypothesis. The data do not provide sufficient
evidence that the average distance is greater than 160 yards. |
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B.
Reject the null hypothesis. The data does provide sufficient evidence that
the average distance is greater than 160 yards.
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C.
t= 1.2334; Critical value = 1.992
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D.
Insufficient information to answer this question.
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Question
38 of 40
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2.5 Points
|
A
golfer wished to find a ball that would travel more than 170 yards when hit
with his 6-iron with a club head speed of 90 miles per hour. He had a golf
equipment lab test a low compression ball by having a robot swing his club 12
times at the required speed. State the null and alternative hypotheses for this
test.
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A.
H0:
µ > 170; Ha: µ = 170
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B.
H0:
µ < 170; Ha: µ = 170
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C.
H0:
µ = 170; Ha: µ > 170
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D.
H0:
µ = 160; Ha: µ >
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Question
39 of 40
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2.5 Points
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A
large test statistic F tells us that the sample means __________ the data
within the individual samples, which would be unlikely if the populations means
really were equal (as the null hypothesis claims).
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A.
differ more than
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B.
differ less than
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C.
are equal to
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D.
do not vary with
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Question
40 of 40
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2.5 Points
|
A
95% confidence interval for the mean of a normal population is found to be 13.2
< µ < 22.4. What is the margin of error?
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A.
4.6
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B.
4.4
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C.
4.2
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D.
5.6
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