BUS 240 TEST 4 QUESTIONS AND ANSWERS
A national manufacturer of ball bearings is experimenting with two different processes for producing
precision ball bearings. It is important that the diameters be as close as possible to an industry standard.
The output from each process is sampled and the average error from the industry standard is measured
in millimeters. The results are shown on the table. The researcher is interested in determining whether
there is evidence that the two processes yield different average errors. The population standard
deviations are unknown but are assumed equal. If we test the null hypothesis at the 1% level of
significance, what is the decision? - CORRECT ANSWER✅✅✅Reject the null hypothesis and conclude
the means are different.
Twenty randomly selected statistics students were given 15 multiple-choice questions and 15 open-
ended questions, all on the same material. The professor was interested in determining if students
scored higher on the multiple-choice questions. This experiment is an example of ________________. -
CORRECT ANSWER✅✅✅A paired t-test
A recent study focused on the number of times men and women send a Twitter message in a day. The
sample information is summarized below. We want to know if, at the .01 significance level, is there a
difference in the mean number of times men and women send a Twitter message in a day. What is the
test statistic for this hypothesis? - CORRECT ANSWER✅✅✅z-statistic
Accounting procedures allow a business to evaluate its inventory costs based on two methods: LIFO
(Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in
$000s) for five products with the LIFO and FIFO methods. To analyze the difference, they computed
(FIFO - LIFO) for each product. Based on the following results, and testing if the LIFO method result in a
lower cost of inventory than the FIFO method. What is the decision at the 5% level of significance? -
CORRECT ANSWER✅✅✅Fail to reject the null hypothesis.
Which condition must be met to conduct a test for the difference in two sample means using a z-
statistic? - CORRECT ANSWER✅✅✅The two population standard deviations must be known.
A national manufacturer of ball bearings is experimenting with two different processes for producing
precision ball bearings. It is important that the diameters be as close as possible to an industry standard.
The output from each process is sampled and the average error from the industry standard is measured
in millimeters. The results are shown on the table. The researcher is interested in determining whether
there is evidence that the two processes yield different average errors. The population standard
deviations are unknown but are assumed equal. What is the computed value of t? - CORRECT
ANSWER✅✅✅-3.299
,Accounting procedures allow a business to evaluate their inventory costs based on two methods: LIFO
(Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in
$000s) for five products with the LIFO and FIFO methods. To analyze the difference, they computed
(FIFO - LIFO) for each product. Based on the following results, and testing if the LIFO method result in a
lower cost of inventory than the FIFO method. What are the degrees of freedom? - CORRECT
ANSWER✅✅✅4
For a hypothesis comparing two population means, H0: μ1 ≤ μ2, what is the critical value for a one-tailed
hypothesis test, using a 5% significance level, with both sample sizes equal to 13? Assume the
population standard deviations are equal. - CORRECT ANSWER✅✅✅1.711
A national manufacturer of ball bearings is experimenting with two different processes for producing
precision ball bearings. It is important that the diameters be as close as possible to an industry standard.
The output from each process is sampled and the average error from the industry standard is measured
in millimeters. The results are shown on the table The researcher is interested in determining whether
there is evidence that the two processes yield different average errors. The population standard
deviations are unknown but are assumed equal. This example is what type of test? - CORRECT
ANSWER✅✅✅A two-sample test of means
An investigation of the effectiveness of a training program to improve customer relationships included a
pre-training and post-training customer survey. To compare the differences, they computed (post-
training survey score - pre-training survey score). Seven customers were randomly selected and
completed both surveys. The results follow.
This analysis is an example of _____________ - CORRECT ANSWER✅✅✅A paired t-test
For a hypothesis test comparing two population means, the combined degrees of freedom are 24.
Which of the following statements about the two sample sizes is NOT true? Assume the population
standard deviations are equal. - CORRECT ANSWER✅✅✅n1 = 11; n2 = 13
An investigation of the effectiveness of a training program to improve customer relationships included a
pre-training and post-training customer survey. To compare the differences they computed (post-
training survey score - pre-training survey score). Seven customers were randomly selected and
completed both surveys. The results follow. What is the value of the test statistic? - CORRECT
ANSWER✅✅✅2.542
, The results of a mathematics placement exam at two different campuses of Mercy College follow: What
is the computed value of the test statistic? - CORRECT ANSWER✅✅✅3.37
A recent study focused on the number of times men and women send a Twitter message in a day. The
information is summarized next. At the .01 significance level, testing if there a difference in the mean
number of times men and women send a Twitter message in a day. What is the value of the test statistic
for this hypothesis test? - CORRECT ANSWER✅✅✅2.4
When is it appropriate to use the paired difference t-test? - CORRECT ANSWER✅✅✅When two
dependent samples are compared
If the null hypothesis that two means are equal is true, where will 97% of the computed z values lie
between? - CORRECT ANSWER✅✅✅±2.17
An investigation of the effectiveness of a training program to improve customer relationships included a
pre-training and post-training customer survey. To compare the differences they computed (post-
training survey score - pre-training survey score). Seven customers were randomly selected and
completed both surveys. The results follow. For a 0.05 significance level, what is the decision regarding
the hypothesis that the training was effective in improving customer relationships? - CORRECT
ANSWER✅✅✅Reject the null hypothesis and conclude that the training was effective.
Two samples, one of size 14 and the second of size 13, are selected to test the difference between two
population means. How many degrees of freedom are used to find the critical value? Assume the
population standard deviations are equal. - CORRECT ANSWER✅✅✅25
Assuming the population variances are known, the population variance of the difference between two
means is _____________. - CORRECT ANSWER✅✅✅The sum of the two population variances
A recent study focused on the number of times men and women send a Twitter message in a day. The
sample information is summarized below. We want to know if, at the .01 significance level, is there a
difference in the mean number of times men and women send a Twitter message in a day. What is the
p-value for this hypothesis test? - CORRECT ANSWER✅✅✅0.0164
A national manufacturer of ball bearings is experimenting with two different processes for producing
precision ball bearings. It is important that the diameters be as close as possible to an industry standard.
The output from each process is sampled and the average error from the industry standard is measured
in millimeters. The results are shown on the table. The researcher is interested in determining whether
there is evidence that the two processes yield different average errors. The population standard
deviations are unknown but are assumed equal. If we test the null hypothesis at the 1% level of
significance, what is the decision? - CORRECT ANSWER✅✅✅Reject the null hypothesis and conclude
the means are different.
Twenty randomly selected statistics students were given 15 multiple-choice questions and 15 open-
ended questions, all on the same material. The professor was interested in determining if students
scored higher on the multiple-choice questions. This experiment is an example of ________________. -
CORRECT ANSWER✅✅✅A paired t-test
A recent study focused on the number of times men and women send a Twitter message in a day. The
sample information is summarized below. We want to know if, at the .01 significance level, is there a
difference in the mean number of times men and women send a Twitter message in a day. What is the
test statistic for this hypothesis? - CORRECT ANSWER✅✅✅z-statistic
Accounting procedures allow a business to evaluate its inventory costs based on two methods: LIFO
(Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in
$000s) for five products with the LIFO and FIFO methods. To analyze the difference, they computed
(FIFO - LIFO) for each product. Based on the following results, and testing if the LIFO method result in a
lower cost of inventory than the FIFO method. What is the decision at the 5% level of significance? -
CORRECT ANSWER✅✅✅Fail to reject the null hypothesis.
Which condition must be met to conduct a test for the difference in two sample means using a z-
statistic? - CORRECT ANSWER✅✅✅The two population standard deviations must be known.
A national manufacturer of ball bearings is experimenting with two different processes for producing
precision ball bearings. It is important that the diameters be as close as possible to an industry standard.
The output from each process is sampled and the average error from the industry standard is measured
in millimeters. The results are shown on the table. The researcher is interested in determining whether
there is evidence that the two processes yield different average errors. The population standard
deviations are unknown but are assumed equal. What is the computed value of t? - CORRECT
ANSWER✅✅✅-3.299
,Accounting procedures allow a business to evaluate their inventory costs based on two methods: LIFO
(Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in
$000s) for five products with the LIFO and FIFO methods. To analyze the difference, they computed
(FIFO - LIFO) for each product. Based on the following results, and testing if the LIFO method result in a
lower cost of inventory than the FIFO method. What are the degrees of freedom? - CORRECT
ANSWER✅✅✅4
For a hypothesis comparing two population means, H0: μ1 ≤ μ2, what is the critical value for a one-tailed
hypothesis test, using a 5% significance level, with both sample sizes equal to 13? Assume the
population standard deviations are equal. - CORRECT ANSWER✅✅✅1.711
A national manufacturer of ball bearings is experimenting with two different processes for producing
precision ball bearings. It is important that the diameters be as close as possible to an industry standard.
The output from each process is sampled and the average error from the industry standard is measured
in millimeters. The results are shown on the table The researcher is interested in determining whether
there is evidence that the two processes yield different average errors. The population standard
deviations are unknown but are assumed equal. This example is what type of test? - CORRECT
ANSWER✅✅✅A two-sample test of means
An investigation of the effectiveness of a training program to improve customer relationships included a
pre-training and post-training customer survey. To compare the differences, they computed (post-
training survey score - pre-training survey score). Seven customers were randomly selected and
completed both surveys. The results follow.
This analysis is an example of _____________ - CORRECT ANSWER✅✅✅A paired t-test
For a hypothesis test comparing two population means, the combined degrees of freedom are 24.
Which of the following statements about the two sample sizes is NOT true? Assume the population
standard deviations are equal. - CORRECT ANSWER✅✅✅n1 = 11; n2 = 13
An investigation of the effectiveness of a training program to improve customer relationships included a
pre-training and post-training customer survey. To compare the differences they computed (post-
training survey score - pre-training survey score). Seven customers were randomly selected and
completed both surveys. The results follow. What is the value of the test statistic? - CORRECT
ANSWER✅✅✅2.542
, The results of a mathematics placement exam at two different campuses of Mercy College follow: What
is the computed value of the test statistic? - CORRECT ANSWER✅✅✅3.37
A recent study focused on the number of times men and women send a Twitter message in a day. The
information is summarized next. At the .01 significance level, testing if there a difference in the mean
number of times men and women send a Twitter message in a day. What is the value of the test statistic
for this hypothesis test? - CORRECT ANSWER✅✅✅2.4
When is it appropriate to use the paired difference t-test? - CORRECT ANSWER✅✅✅When two
dependent samples are compared
If the null hypothesis that two means are equal is true, where will 97% of the computed z values lie
between? - CORRECT ANSWER✅✅✅±2.17
An investigation of the effectiveness of a training program to improve customer relationships included a
pre-training and post-training customer survey. To compare the differences they computed (post-
training survey score - pre-training survey score). Seven customers were randomly selected and
completed both surveys. The results follow. For a 0.05 significance level, what is the decision regarding
the hypothesis that the training was effective in improving customer relationships? - CORRECT
ANSWER✅✅✅Reject the null hypothesis and conclude that the training was effective.
Two samples, one of size 14 and the second of size 13, are selected to test the difference between two
population means. How many degrees of freedom are used to find the critical value? Assume the
population standard deviations are equal. - CORRECT ANSWER✅✅✅25
Assuming the population variances are known, the population variance of the difference between two
means is _____________. - CORRECT ANSWER✅✅✅The sum of the two population variances
A recent study focused on the number of times men and women send a Twitter message in a day. The
sample information is summarized below. We want to know if, at the .01 significance level, is there a
difference in the mean number of times men and women send a Twitter message in a day. What is the
p-value for this hypothesis test? - CORRECT ANSWER✅✅✅0.0164
