Question 1
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.
A. Conclusion: Support the claim that the mean is less than 9.4 minutes.
B. Conclusion: Support the claim that the mean is greater than 9.4 minutes.
C. Conclusion: Support the claim that the mean is equal to 9.4 minutes.
D. Conclusion: Do not support the claim that the mean is greater than 9.4 minutes.
A two-tailed test is conducted at the 5% significance level. What is the P-value required to reject
Question 2
the null hypothesis?
A. Greater than or equal to 0.10
B. Less than or equal to 0.05
C. Less than or equal to 0.10
D. Greater than or equal to 0.05
A nationwide study of American homeowners revealed that 65% have one or more lawn mowers.
Question 3
A lawn equipment manufacturer, located in Omaha, feels the estimate is too low for households
in Omaha. Find the P-value for a test of the claim that the proportion with lawn mowers in
Omaha is higher than 65%. Among 497 randomly selected homes in Omaha, 340 had one or more
lawn mowers. Use Table 5.1 to find the best answer.
A. 0.0559
B. 0.1118
C. 0.0252
D. 0.0505
Question 4
The principal of a middle school claims that annual incomes of the families of the seventhgraders
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 = $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.
A. The current seventh graders at the principal's school
B. Seventh graders' families at the school with a standard deviation of $13,700
C. All of the families of the class of seventh graders at the principal's school
D. All seventh graders' families
Question 5
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.
A. Do not reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months is supported.
B. Do not reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months cannot be supported.
C. Reject the null hypothesis and conclude that the claim that the mean is different from 18.7
months is supported.
D. Reject the null hypothesis and conclude that the claim that the mean is different from 18.7
months cannot be supported.
Question 6
In the past, the mean running time for a certain type of flashlight battery has been 9.8 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:
Suppose that the results of the sampling lead to rejection of the null hypothesis. Classify that
conclusion as a Type I error, a Type II error, or a correct decision, if in fact the mean running
time has not increased.
A. Type I error
B. Type II error
C. Correct decision
D. Can not be determined from this information
Question 7
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.
Question
A right-tailed test is conducted at the 5% significance level. Which of the following z-scores is
the smallest one in absolute value that leads to rejection of the null hypothesis?
A. 1.61
B. 1.85
C. -1.98
D. -2.06
Question 9
A study of a brand of "in the shell peanuts" gives the following results:
A significant event at the 0.01 level is a fan getting a bag with how many peanuts?
A. 30 peanuts
B. 25 or 30 peanuts
C. 25 or 55 peanuts
D. 25 peanuts
A psychologist claims that more than 19 percent of the population suffers from professional
Question 10
problems due to extreme shyness. 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.
A. The population is all shy workers.
B. The population cannot be identified from the description of the study.
C. The population is all American workers.
D. The population is all American professional workers (doctors, lawyers, CPA's, and the like..
Question 11
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.
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 that ??= 4.8 minutes.
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.
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.
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.
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.
Question 13
If a fan purchased a bag with 30 peanuts, what is the lowest level at which this would be a
significant event?
A. 0.05
B. 0.025
C. 0.01
D. It is not significant at any of the levels given
The owner of a football team claims that the average attendance at home games is over 3000, and
Question 14
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.
A. There is sufficient evidence to support the claim that the mean attendance is greater than
3000.
B. There is sufficient evidence to support the claim that the mean attendance is equal to 3000.
C. There is not sufficient evidence to support the claim that the mean attendance is greater than
3000.
D. There is not sufficient evidence to support the claim that the mean attendance is less than
3000.
Question 15
A manufacturer claims that the mean amount of juice in its 16 ounce bottles is 16.1 ounces. A
consumer advocacy group wants to perform a hypothesis test to determine whether the mean
amount is actually less than this. The mean volume of juice for a random sample of 70 bottles
was 15.94 ounces. Do the data provide sufficient evidence to conclude that the mean amount of
juice for all 16-ounce bottles, µ, is less than 16.1 ounces? Perform the appropriate hypothesis test
using a significance level of 0.10. Assume that ? = 0.9 ounces.
A. The z of ? 1.49 provides sufficient evidence to conclude that the mean amount of juice is less than 16.1 oz.
B. The z of ? 1.49 does not provide sufficient evidence to conclude that the mean amount of juice is less than 16.1 oz.
C. The z of ? 0.1778 does not provide sufficient evidence to conclude that the mean amount of juice is less than 16.1 oz.
D. The z of ? 0.1778 provides sufficient evidence to conclude that the mean amount of juice is less than 16.1 oz.
A psychologist claims that more than 29 percent of the professional population suffers from
Question 16
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.
A. There is sufficient evidence to support the claim that the true proportion is less than 29
percent.
B. There is not sufficient evidence to support the claim that the true proportion is greater than 29
percent.
C. There is sufficient evidence to support the claim that the true proportion is equal to 29 percent.
D. There is sufficient evidence to support the claim that the true proportion is greater than 29
percent.
The owner of a football team claims that the average attendance at home games is over 4000, and
Question 17
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.
A. All games played by the team in question in which the attendance is over 4000
B. All future home games to be played by the team in question
C. All home games played by the team in question
D. None of the populations given are appropriate
Question 18
without computing a P-value, determine whether the alternate hypothesis is supported and give a
reason for your conclusion.
is less than 1 standard deviation above the claimed mean.
is more than 4 standard deviations above the claimed mean.
is less than 1 standard deviation above the claimed mean.
is more than 4 standard deviations above the claimed mean.
Question 19
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.
Question 21
Which of the following statements is true?
A. The t distribution can be used when finding a confidence interval for the population mean
whenever the sample size is small.
B. The p distribution can be used when finding a confidence interval for the population mean
whenever the sample size is small.
C. The t distribution cannot be used when finding a confidence interval for the population mean
whenever the sample size is small.
D. The p distribution cannot be used when finding a confidence interval for the sample mean
whenever the sample size is small.
Question 22
A 95% confidence interval for the mean of a normal population is found to be 15.6 < µ < 24.8.
What is the margin of error?
A. 4.4
B. 4.6
C. 4.8
D. 5.0
The __________ test statistic is for the one-way analysis of variance.
Question 23
A. P-Value
B. t
C. F
D. p
Question 24
A simple random sample from a normal distribution is taken in order to obtain a 95% confidence
interval for the population mean. If the sample size is 8, the sample mean x is 22, and the sample
standard deviation s is 6.3, what is the margin of error? Show your answer to 2 decimal places.
A. df = 7; E = 3.3445.38 = 5.6566
B. df = 8; E = 3.3445.38 = 5.6566
C. df = 6; E = 2.3656.38 = 5.769
D. df = 7; E = 2.3656.38 = 5.869
Question 25
One hundred people are selected at random and tested for colorblindness to determine whether
gender and colorblindness are independent. The following counts were observed.
Colorblind Not Colorblind Total
Male 7 53 60
Female 1 39 40
Total 8 92 100
Find the value of the X
A. 1.325
B. 1.318
C. 1.286
D. 1.264
Question 26
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?
A. 4.6
B. 4.4
C. 4.2
D. 5.6
Question 27
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.
Data from this test had a sample mean of 171.6 yards with a sample standard deviation of 2.4
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.
Area in one tail
Area in two tails
Degrees of
Freedom
Accept the null hypothesis. The data do not provide sufficient evidence that the average distance
is greater than 170 yards.
B. Accept the null hypothesis. The data do provide sufficient evidence that the average distance
is greater than 170 yards.
C. Reject the null hypothesis. The data do not provide sufficient evidence that the average
distance is greater than 170 yards.
D. Reject the null hypothesis. The data do provide sufficient evidence that the average distance is
greater than 170 yards.
Question 28
One hundred people are selected at random and tested for colorblindness to determine whether
gender and colorblindness are independent.
The critical value of X 2 for a 2 x 2 table using a 0.05 significance level is 3.841. If the value of
the X 2 statistic is 3.179, state your conclusion about the relationship between gender and
colorblindness..
There is sufficient evidence to support the claim that gender and colorblindness are not related.
D. There is not sufficient evidence to accept or reject H
Question 29
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.
Question 30
The following data were analyzed using one-way analysis of variance.
A B C
34 27 19
26 23 21
31 29 22
28 21 12
Which one of the following statements is correct?
A. The purpose of the analysis is to determine whether the groups A, B, and C are independent.
B. The purpose of the analysis is to test the hypothesis that the population means of the three
groups are equal.
C. The purpose of the analysis is to test the hypothesis that the population variances of the three
groups are equal.
D. The purpose of the analysis is to test the hypothesis that the sample means of the three groups
are equal.
Question 31
One hundred people are selected at random and tested for colorblindness to determine whether
gender and colorblindness are independent. The following counts were observed.
Colorblind Not Colorblind Total
Male 7 53 60
Female 1 39 40
Total 8 92 100
If gender and colorblindness are independent, find the expected values corresponding to the male
combinations of gender and colorblindness.
A. Colorblind Male 4.8; Not Colorblind Male 55.2
B. Colorblind Male 6.8; Not Colorblind Male 53.2
C. Colorblind Male 4.8; Not Colorblind Male 55.4
D. Colorblind Male 4.8; Not Colorblind Male 56.2
Question 32
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.
A.
Reject the null hypothesis. The data do not provide sufficient evidence that the average distance
is greater than 180 yards.
B. Reject the null hypothesis. The data do provide sufficient evidence that the average distance is
greater than 180 yards.
C. Do not reject the null hypothesis. The data do provide sufficient evidence that the average
distance is greater than 180 yards.
D. Do not reject the null hypothesis. The data do not provide sufficient evidence that the average
distance is greater than 180 yards.
Question 33
One hundred people are selected at random and tested for colorblindness to determine whether
gender and colorblindness are independent.
The critical value of X 2 for a 2 x 2 table using a 0.05 significance level is 3.841. If the value of
the X 2 statistic is 4.613, state your conclusion about the relationship between gender and
colorblindness.
A. Reject H
There is not sufficient evidence to support the claim that gender and colorblindness
are related.
B. Reject H
There is sufficient evidence to support the claim that gender and colorblindness are
related.
C. Do not Reject H.