BUS308 Statistics for Managers
Ashford University
Ashford BUS308 Week 1 Discussion
Descriptive Statistics: Case Problem Business
Schools of Asia-Pacific
Prior to beginning work on this discussion
forum, watch the Week 1 Introduction (Links to an external site.) video, and read Chapters 1, 2, and 3 in
the MindTap ebook by clicking on the Getting Ready link for
each chapter. You can access the MindTap ebook, Essentials
of Modern Business Statistics with Microsoft® Excel®, in your online classroom.
Step 1: Read:
·
Review Case
Problem 3: Business Schools of Asia-Pacific 
download from Chapter 3 in the ebook.
Step 2: Do:
·
Run descriptive
statistics for the Data File AsiaMBA (Chapter 3) using the video How to Add Excel's Data
Analysis ToolPak. (Links to an external site.)
In a managerial report, use the methods of
descriptive statistics to
·
Summarize the data in
Data File AsiaMBA.
·
Summarize each
variable in the data set.
Step 3: Discuss:
·
What new insights do
these descriptive statistics provide concerning Asia-Pacific business schools?
You should also analyze differences between local and foreign tuition costs,
between mean starting salaries for schools requiring and not requiring work
experience, and between starting salaries for schools requiring and not
requiring English tests.
Ashford BUS308 Week 4 TourisTopia (chapter 13)
Multiple Regression: Case Problem Predicting
Winnings for NASCAR Drivers [WLOs: 1, 2, 3] [CLOs: 1, 2, 3, 4, 5, 6, 7]
Prior to beginning work on this discussion
forum, watch the Week 5 Introduction (Links to an external site.) video, and read Chapter 15 in the
MindTap ebook by clicking on the Getting Ready link for each
perspective chapter.
Step 1: Read
·
Review Case
Problem 2: Predicting Winnings for NASCAR Drivers download from Chapter 15 of the ebook.
Step 2: Do
·
Run a Regression for
the Data File NASCAR (Chapter 15) using the video How to Add Excel's Data Analysis
ToolPak (Links to an external site.) for assistance.
In a managerial report,
·
Suppose you wanted to
predict Winnings ($) using only the number of poles won (Poles), the number of
wins (Wins), the number of top five finishes (Top 5), or the number of top ten
finishes (Top 10). Which of these four variables provides the best single
predictor of winnings?
·
Develop an estimated
regression equation that can be used to predict Winnings ($) given the number
of poles won (Poles), the number of wins (Wins), the number of top five
finishes (Top 5), and the number of top ten (Top 10) finishes. Test for
individual significance, and then discuss your findings and conclusions.
Step 3: Discuss:
·
What did you find in
your analysis of the data? Were there any surprising results? What
recommendations would you make based on your findings? Include details from
your managerial report to support your recommendations.
Ashford BUS308 Week 1 Exercise 03.45
The New
York Times reported that Apple has unveiled a new iPad marketed specifically to
school districts for use by students (The New York Times website). The -inch
iPads will have faster processors and a cheaper price point in an effort to
take market share away from Google Chromebooks in public school districts.
Suppose that the following data represent the percentages of students currently
using Apple iPads for a sample of U.S. public school districts.
Click on the datafile logo to reference the data.
a. Compute the mean and median percentage of students currently using Apple
iPads.
b. Compute the first and third quartiles for these data.
c. Compute the range and interquartile range for these data.
d. Compute the variance and standard deviation for these data.
e. Are there any outliers in these data? Enter the number of outliers. If an
amount is zero, enter "0".
f. Based on your calculated values, what can we say about the percentage of
students using iPads in public school districts?
Ashford BUS308 Week 1 Exercise 03.67
Public
transportation and the automobile are two methods an employee can use to get to
work each day. Samples of travel times recorded for each method are shown.
Times are in minutes.
a. Compute the sample mean time to get to work for each method (to the nearest
whole number).
b. Compute the sample standard deviation for each method (to decimals).
c. On the basis of your results from parts (a) and (b), which method of
transportation should be preferred? Explain.
d. Select a boxplot for each method.
Does a comparison of the boxplots support your conclusion in part (c)?
BUS308 Predictive Sales Report
Predictive Sales
Report
A retail store has recently hired you as a consultant to advise on economic
conditions. One important indicator that the retail store is concerned about is
the unemployment rate. The retail store has found that an increase in the
unemployment rate will cause a lack of consumer spending in their stores.
Retail stores use the unemployment rate to estimate how much inventory to keep
at their stores, which is important in maintaining cost effectiveness. In this
consultant role you will apply calculations and research to create a predictive
sales report.
You will complete this project in two parts, but will submit your work as one
Word document. Copy and paste your calculations from your Excel workbook into
the Word document.
The Final Project must be eight to ten pages in length, excluding title page
and reference page(s) and must include at least three scholarly sources, in
addition to the Job and Labor Statistics site. Be sure to format your work in
accordance with APA guidelines as outlined in the Ashford Writing Center.
Part I
Reference the data in this Excel Workbook to complete the following
quantitative components of the predictive sales report. You will complete the
calculations below in your own Excel workbook and then copy and paste from your
Excel workbook into the Word document.
Calculate the mean yearly value using the average unemployment rate by month found
in the "Final Project Data Set."
Using the years as your x-axis and the annual mean as your y-axis, create a
scatter plot and a linear regression line.
Answer the following questions using your scatter plot and linear regression
line:
Compute the slope of the linear regression line.
Identify the Y-intercept of the linear regression line.
Identify the equation of the linear regression line in slope-intercept form.
Calculate the unemployment rate in 2016, based on the linear regression line.
Calculate the residuals of each year.
Find the latest unemployment rate in your state. You will need to go to the
Bureau of Labor Statistics Website (www.bls.gov)and
hover over "Subject Areas" in the top menu panel then select
"State and Local Unemployment Rates" from the drop down menu under
"Unemployment Rate". Determine whether the rate in your state is
within the range of the linear regression line or if it is an outlier.
Interpret your results of the model and explain how a company could use the
results to drive decision making.
PART II
Next interpret the analysis from Part I to complete the following qualitative
components of the predictive sales report:
Introduce the project and its significance to the retail store.
Reference the statistical analysis that you completed in Part I and explain
where the data came from, what type of analysis was done, what the findings
were, and whether or not you believe the data to be accurate.
Explain your data-driven conclusions regarding the effects of the changing
unemployment rate on the retail store.
Predict what could occur in the future that would change your linear regression
line and therefore your prediction of sales.
Writing the Final Paper
The Final Paper:
Part I must be calculated in an Excel spreadsheet and then copied and pasted
into your single Word document. You must show all work and clearly label all
calculations. Excel documents will not be graded.
Part II must be double-spaced and formatted according with APA guidelines as
outlined in the Ashford Writing Center. Part II should be included in the same
Word document as your calculations.
Your Final Project in its entirety should be eight to ten pages in length
excluding title page and reference page(s) and including all calculations.
Must include a cover page that includes:
- Title of paper
- Student's name
- Course name and number
- Instructor's name
- Date submitted
Must include an introductory paragraph with a succinct thesis statement.
Must address the topic of the paper with critical thought.
Must conclude with a restatement of the thesis and a conclusion paragraph.
Must use at least three scholarly resources, in addition to the Job and Labor
Statistics site, from the Ashford Library or other scholarly sources. Resources
must be properly cited in APA guidelines as outlined in the Ashford Writing
Center.
Must use APA style as outlined in the approved APA style guide to document all
sources.
Must include, on the final page, a Reference Page that is completed according
to APA style as outlined in the approved APA style guide.
You must submit your work in one Word document that includes Part I and Part
II.
Additional Requirements
Min Pages: 8
Max Pages: 10
Ashford BUS308 Week 1 Assignment
Exercise 03.31 (Measures of Variability)
According to the
Consumer Expenditure Survey, Americans spend an average of on cellular phone
service annually (U.S. Bureau of Labor Statistics website). Suppose that we
wish to determine if there are differences in cellular phone expenditures by
age group. Therefore, samples of consumers were selected for three age groups (
, , and older). The annual expenditure for each person in the sample is
provided in the table below.
Click on the datafile logo to reference the data.
a. Compute the mean, variance, and standard deviation for each of these three
samples. Round your answers to one decimal place.
b. What observations can be made based on these data?
The age group that spends the least amount on cellular phone service is
and the age group that spends the biggest amount on cellular phone service is
Ashford BUS308 Week 2 Discussion
Hypothesis Testing Case Problem PAR Inc
Prior
to beginning work on this discussion forum, watch the Week
2 Introduction (Links
to an external site.) video,
and read Chapters 9 and 10 in the MindTap ebook by clicking on the Getting
Ready link for each perspective chapter.
Step
1: Read:
·
Review Case Problem: PAR Inc. download from Chapter 10 in the ebook.
Step
2: Do:
·
Run the t-Test:
Two-Sample Assuming Unequal Variances for the Data File Golf (Chapter 10) using
the video How
to Add Excel's Data Analysis ToolPak (Links to an external site.) for assistance.
In a
managerial report, use the methods of hypothesis testing to
·
Formulate and
present the rationale for a hypothesis test that Par could use to compare the
driving distances of the current and new golf balls.
·
Analyze the data to
provide the hypothesis testing conclusion. What is the p-value for your test?
What is your recommendation for Par, Inc.?
·
Provide descriptive
statistical summaries of the data for each model.
·
Explain what the 95%
confidence interval is for the population mean driving distance of each model,
and explain what the 95% confidence interval is for the difference between the
means of the two populations.
·
Discuss whether you
see a need for larger sample sizes and more testing with the golf balls.
Step
3: Discuss
Based
on your hypothesis testing conclusion, what are your recommendations for Par,
Inc? Support your recommendations with findings from your managerial report.
Ashford BUS308 Week 2 Chapter 9 Assignment
SCORE 100%
Question 1: Exercise 09.03 (Developing Null and
Alternative Hypotheses)
A production line operation is designed to
fill cartons with laundry detergent to a mean weight of ounces. A sample of
cartons is periodically selected and weighed to determine whether underfilling
or overfilling is occurring. If the sample data lead to a conclusion of
underfilling or overfilling, the production line will be shut down and adjusted
to obtain proper filling.
a. Formulate the null and alternative
hypotheses that will help in deciding whether to shut down and adjust the
production line.
b. Comment on the conclusion when cannot be rejected. Is there
evidence that the production line is not operating properly?
c. Comment on the conclusion when can be rejected. Can we conclude
that overfilling or underfilling exists?
Question
2 Exercise 09.07 (Type I and Type II Errors)
Carpetland salespersons average per week in
sales. Steve Contois, the firm's vice president, proposes a compensation plan
with new selling incentives. Steve hopes that the results of a trial selling
period will enable him to conclude that the compensation plan increases the
average sales per salesperson.
a. Develop the appropriate null and alternative hypotheses.
:
:
b. What is the Type I error in this situation?
In this situation, a Type I error would occur
if it was concluded that the new compensation plan provides a population mean
weekly sales
when in fact it does not.
What are the consequences of making this
error?
c. What is the Type II error in this situation?
In this situation, a Type II error would occur
if it was concluded that the new compensation plan provides a population mean
weekly sales
when in fact it does not.
What are the consequences of making this
error?
Question
3 Exercise 09.19 (Population Mean: Sigma Known)
According to the IRS, taxpayers calling the
IRS in waited minutes on average for an IRS telephone assister to answer. Do
callers who use the IRS help line early in the day have a shorter wait? Suppose
a sample of callers who placed their calls to the IRS in the first minutes that
the line is open during the day have a mean waiting time of minutes before an
IRS telephone assister answers. Based on data from past years, you decide that
it is reasonable to assume that the standard deviation of waiting times is
minutes. Using these sample results, can you conclude that the waiting time for
calls placed during the first minutes the IRS help line is open each day is
significantly less than the overall mean waiting time of minutes? Use .
State the hypotheses.
: What is the p-value (to decimals)?
Can you conclude that callers who use the IRS
help-line early in the day have a shorter wait?
Question 4 Exercise 09.29 (Population Mean:
Sigma Unknown)
On its municipal website, the city of Tulsa
states that the rate it charges per CCF of residential water is . How do the
residential water rates of other U.S. public utilities compare to Tulsa's rate?
The file ResidentialWater contains the rate per CCF of
residential water for randomly selected U.S. cities.
Click on the datafile logo to reference the
data.
a. Formulate hypotheses that can be used to determine whether the
population mean rate per CCF of residential water charged by U.S. public
utilities differs from the rate charged by Tulsa.
Choose the correct null hypothesis:
1. :
2. :
3. :
Choose the correct alternative hypothesis:
1. :
2. :
3. :
b. What is the -value for your hypothesis test in part (a)? Round
your answer to four decimal places.
c. At , can your null hypothesis be rejected? What is your conclusion?
the null hypothesis. The mean rate per CCF of
residential water throughout the U.S.
significantly from the rate per CCF of
residential water in Tulsa.
d. Repeat the preceding hypothesis test using the critical value
approach.
The critical value(s) is(are)
.
= (to
decimals),
the null hypothesis.
Question
5 Exercise 09.43 (Population Proportion)
Eagle Outfitters is a chain of stores
specializing in outdoor apparel and camping gear. They are considering a
promotion that involves mailing discount coupons to all its credit card
customers. This promotion will be considered a success if more than of those
receiving the coupons use them. Before going national with the promotion,
coupons were sent to a sample of credit card customers.
Click on the datafile logo to reference the
data.
a. Develop hypotheses that can be used to test whether the
population proportion of those who will use the coupons is sufficient to go
national.
:
:
b. The file Eagle contains the sample data.
Develop a point estimate of the population proportion (to decimals).
c. Use to conduct your hypothesis test. Should Eagle go
national with the promotion?
Question
6 Exercise 09.51 (Population Mean: Sigma Known)
At Western University the historical mean of
scholarship examination scores for freshman applications is . A historical
population standard deviation is assumed known. Each year, the assistant dean
uses a sample of applications to determine whether the mean examination score
for the new freshman applications has changed.
a. State the hypotheses.
:
:
b. What is the confidence interval estimate of the population
mean examination score if a sample of applications provided a sample mean of
(to the nearest whole number)?
( , )
c. Use the confidence interval to conduct a
hypothesis test. Using , can the assistant dean conclude that the mean
examination score for the new freshman applications has changed?
d. What is the -value (to decimals)? (Use Table 1 from Appendix B.)
Question
7 Exercise 09.57 (Population Mean: Sigma Unknown)
According to the National Association of
Realtors, it took an average of three weeks to sell a home in . Data for the
sale of randomly selected homes sold in Greene County, Ohio, in showed a sample
mean of weeks with a sample standard deviation of weeks. Conduct a hypothesis
test to determine whether the number of weeks until a house sold in Greene
County differed from the national average in . Round your answer to four
decimal places.
p-value =
Use for the level of significance, and state
your conclusion.
I.Reject
. There is a statistically significant difference between the national average
time to sell a home and the mean time to sell a home in Greene County.
II.Reject
. There is not a statistically significant difference between the national
average time to sell a home and the mean time to sell a home in Greene County.
III.Do
not reject . There is a statistically significant difference between the
national average time to sell a home and the mean time to sell a home in Greene
County.
IV.Do
not reject . There is not a statistically significant difference between the
national average time to sell a home and the mean time to sell a home in Greene
County.
Choose the correct option.
Ashford BUS308 Week 2 Chapter 10 Assignment
Question 1 Exercise
10.07 (Inferences About the Difference Between Two Population Means: Sigmas
Known)
Consumer Reports uses a survey of readers to obtain
customer satisfaction ratings for the nation's largest supermarkets (Consumer
Reports website). Each survey respondent is asked to rate a specified
supermarket based on a variety of factors such as quality of products,
selection, value, checkout efficiency, service, and store layout. An overall
satisfaction score summarizes the rating for each respondent with meaning the
respondent is completely satisfied in terms of all factors. Sample data
representative of independent samples of Publix and Trader Joe's customers are
shown below.
Excel File: data10-07.xlsx
|
Publix |
Trader Joe's |
|
a. Formulate the null and alternative hypotheses to test whether
there is a difference between the population mean customer satisfaction scores
for the two retailers.
b. Assume that experience with the Consumer Reports satisfaction
rating scale indicates that a population standard deviation of is a reasonable
assumption for both retailers. Conduct the hypothesis test and report the
-value.
p-value = (to
decimals)
At a level of significance what is your
conclusion?
I.Reject
. There is not sufficient evidence to conclude that the mean satisfaction
scores differ for the two retailers.
II.Do
not reject . There is not sufficient evidence to conclude that the mean
satisfaction scores differ for the two retailers.
III.Reject
. There is sufficient evidence to conclude that the mean satisfaction scores
differ for the two retailers.
IV.Do
not reject . There is sufficient evidence to conclude that the mean
satisfaction scores differ for the two retailers.
c. Which retailer, if either, appears to have the greater customer
satisfaction?
Provide a confidence interval for the
difference between the population mean customer satisfaction scores for the two
retailers. Enter negative values as negative numbers, if any.
to (to
decimals)
Question 2 Exercise
10.17 (Inferences About the Difference Between Two Population Means: Sigmas
Unknown)
Periodically, Merrill Lynch customers are
asked to evaluate Merrill Lynch financial consultants and services. Higher
ratings on the client satisfaction survey indicate better service with the
maximum service rating. Independent samples of service ratings for two
financial consultants are summarized here. Consultant A has years of
experience, whereas consultant B has year of experience. Use and test to see
whether the consultant with more experience has the higher population mean
service rating. Round degrees of freedom to previous whole number.
Excel File: data10-17.xlsx
|
Consultant A |
Consultant B |
||
a. State the null and alternative hypotheses.
:
:
b. Compute the value of the test statistic. (to 2 decimals)
c. What is the p-value? Use
Table 2 from Appendix B to find the values that bound the test
statistic.
d. What is your conclusion?
Question 3
Exercise 10.27 (Inferences About the Difference Between Two Population
Means: Matched Samples)
A personal fitness produces both a deluxe and
a standard model of a smoothie blender for home use. Selling prices obtained
from a sample of retail outlets follow.
Excel File: data10-27.xlsx
|
Model Price ($) |
Model Price ($) |
|||||
|
Retail Outlet |
Deluxe |
Standard |
Retail Outlet |
Deluxe |
Standard |
|
|
1 |
39 |
27 |
5 |
40 |
30 |
|
|
2 |
39 |
28 |
6 |
39 |
34 |
|
|
3 |
45 |
35 |
7 |
35 |
29 |
|
|
4 |
38 |
30 |
||||
Round your answers to 2 decimal places.
a. The manufacturer's suggested retail prices for the two models
show a price differential. Use a level of significance and test that the mean
difference between the prices of the two models is .
b. What is the confidence interval for the difference between the
mean prices of the two models?
to
Question 4 Exercise
10.29 Algo (Inferences About the Difference Between Two Population Proportions)
Consider the hypothesis test below.
The following results are for independent
samples taken from the two populations.
|
Sample 1 |
Sample 2 |
|
|
|
Use pooled estimator of .
a. What is the -value (to 4 decimals)? Use Table 1 from Appendix B.
b. With , what is your hypothesis testing
conclusion?
Question 5 Exercise
10.41 (Inferences About the Difference Between Two Population Means: Sigmas
Unknown)
The National Association of Home Builders
provided data on the cost of the most popular home remodeling projects. Sample
data on cost in thousands of dollars for two types of remodeling projects are
as follows.
Excel File: data10-41.xlsx
|
Kitchen |
Master Bedroom |
Kitchen |
Master Bedroom |
|
|
25.2 |
18.0 |
23.0 |
17.8 |
|
|
17.4 |
22.9 |
19.7 |
24.6 |
|
|
22.8 |
26.4 |
16.9 |
21.0 |
|
|
21.9 |
24.8 |
21.8 |
||
|
19.7 |
26.9 |
23.6 |
a. Develop a point estimate of the difference between the
population mean remodeling costs for the two types of projects. Enter negative
values as negative numbers.
Point estimate
(Report in dollars with no commas in your answer.)
b. Develop a confidence interval for the difference between
the two population means. (to 1 decimal and enter negative values as negative
numbers)
( , )
in thousands of dollars.
Question 6 Exercise
10.43 (Inferences About the Difference Between Two Population Proportions)
Country Financial, a financial services
company, uses surveys of adults age and older to determine whether personal
financial fitness is changing over time. A recent sample of adults showed
indicating that their financial security was more than fair. Just a year prior,
a sample of adults showed indicating that their financial security was more
than fair.
a. State the hypotheses that can be used to test
for a significant difference between the population proportions for the two
years.
b. Conduct the hypothesis test and compute the -value. Round your
answer to four decimal places.
p-value =
At level of significance, what is your
conclusion?
I.Reject
. There is not sufficient evidence to conclude that the population proportions
are not equal. The data do not suggest that there has been a change in the
population proportion saying that their financial security is more than fair.
II.Reject
. There is sufficient evidence to conclude that the population proportions are
not equal. The data suggest that there has been a change in the population
proportion saying that their financial security is more than fair.
III.Do
not reject . There is not sufficient evidence to conclude that the population
proportions are not equal. The data do not suggest that there has been a change
in the population proportion saying that their financial security is more than
fair.
IV.Do
not reject . There is sufficient evidence to conclude that the population
proportions are not equal. The data suggest that there has been a change in the
population proportion saying that their financial security is more than fair.
c. What is the confidence interval estimate of the difference
between the two population proportions? Round your answers to four decimal
places.
Confidence Interval ( to )
Ashford BUS308 Week 2 10.1 Excel Activity 1
10.1 Excel Activity 1 - Confidence Interval
for Difference of Two Means (Structured)
Condé Nast Traveler conducts an annual survey in which
readers rate their favorite cruise ship. All ships are rated on a 100-point
scale, with higher values indicating better service. A sample of ships that
carry fewer than 500 passengers and a sample of ships that carry 500 or more
passengers is provided in the Microsoft Excel Online file below (Condé Nast
Traveler, February 2008).
Round your all answers to two decimal places.
Open spreadsheet
a.
What is the point
estimate of the difference between the population mean rating for ships that carry
fewer than 500 passengers and the population mean rating for ships that carry
500 or more passengers?
fill in the blank 2
b.
At 95% confidence,
what is the margin of error?
fill in the blank 3
c.
What is a 95%
confidence interval estimate of the difference between the population mean
ratings for the two sizes of ships?
Ashford BUS308 Week 3 Discussion Inferences
About Population Variances
Prior
to beginning work on this discussion forum, watch the Week 3 Introduction (Links to an external site.) video, and read Chapter 11 in the MindTap ebook by
clicking on the Getting Ready link for each perspective
chapter.
Step
1: Read:
·
Review Case
Problem 1: Air Force Training Program download from
Chapter 11 of the ebook.
Step
2: Do:
·
Run the F-Test Two-Sample for
Variances for the Data File Training (Chapter 11) using the video How to Add Excel's Data Analysis
ToolPak (Links to an external site.) for assistance.
In
a managerial report,
·
Use appropriate descriptive
statistics to summarize the training time data for each method. What
similarities or differences do you observe from the sample data?
·
Conduct a hypothesis test on the
difference between the population means for the two methods. Discuss your
findings.
·
Compute the standard deviation and
variance for each training method. Conduct a hypothesis test about the equality
of population variances for the two training methods. Discuss your findings.
·
Explain what conclusion you can
reach about any differences between the two methods. What is your
recommendation? Explain.
·
Suggest other data or testing that
might be desirable before making a final decision on the training program to be
used in the future.
Step
3: Discuss:
·
What did you find in your analysis
of the data? Were there any surprising results? What recommendations would you
make based on your findings? Include details from your managerial report to
support your recommendations.
Ashford BUS308 Week 3 Chapter 11
Assignment
Question 1
Stable
cost reporting in a manufacturing setting is typically a sign that operations
are running smoothly. The accounting department at Rockwell Collins, an
avionics manufacturer, analyzes the variance of the weekly costs reported by
two of its production departments. A sample of cost reports for each of the two
departments shows cost variances of and , respectively. Is this sample
sufficient to conclude that the two production departments differ in terms of
unit cost variance? Use (to decimals).
Question 2
The
competitive advantage of some small American factories such as In Tolerance
Contract Manufacturing lies in their ability to produce parts with very narrow
requirements, or tolerances, that are typical in the aerospace industry.
Consider a product with specifications that call for a maximum variance in the
lengths of the parts of . Suppose the sample variance for parts turns out to be
. Use , to test whether the population variance specification is being
violated.
: Test
statistic = (to
2 decimals, if required)
The
-value is
.
Use Table
11.1.
Question 3
In its Auto Reliability
Survey, Consumer Reports asked subscribers to report their
maintenance and repair costs. Most individuals are aware of the fact that the
average annual repair cost for an automobile depends on the age of the
automobile. A researcher is interested in finding out whether the variance of
the annual repair costs also increases with the age of the automobile. A sample
of automobiles years old showed a sample standard deviation for annual repair
costs of and a sample of automobiles years old showed a sample standard
deviation for annual repair costs of .
a. State the null and alternative versions of the
research hypothesis that the variance in annual repair costs is larger for the
older automobiles. Let year old automobiles be represented by population .
b. At a level of significance, what is your
conclusion?
Calculate the value of
the test statistic (to decimals).
The -value is
. Use Table 4 of Appendix B.
that
year old automobiles have a larger variance in annual repair costs compared to
year old automobiles.
Question 4
The variance in a
production process is an important measure of the quality of the process. A
large variance often signals an opportunity for improvement in the process by
finding ways to reduce the process variance. Jelly Belly Candy Company is
testing two machines that use different technologies to fill three pound bags
of jelly beans. The file Bags contains a sample of data on
the weights of bags (in pounds) filled by each machine.Conduct a statistical
test to determine whether there is a significant difference between the
variances in the bag weights for the two machines. Use a level of significance.
What is your conclusion? Which machine, if either, provides the greater
opportunity for quality improvements? Click on the datafile logo to reference
the data.
(to
decimals)
(to
decimals)
(to
decimals)
Question 5
Battery
life is an important issue for many smartphone owners. Public health studies
have examined "low-battery anxiety" and acute anxiety called
"nomophobia" that results when a smartphone user's phone battery
charge runs low and then dies (Wall Street Journal, May , ). Battery
life between charges for the Samsung Galaxy S9 averages hours when the primary
use is talk time and hours when the primary use is Internet applications.
Because the mean hours for talk time usage is greater than the mean hours for
Internet usage, the question was raised as to whether the variance in hours of
usage is also greater when the primary use is talk time. Sample data showing
battery life between charges for the two applications follows. Click on the
datafile logo to reference the data.
|
Primary Use: Talking |
||||||||||||
|
35.8 |
22.2 |
24.0 |
32.6 |
18.5 |
42.5 |
|||||||
|
28.0 |
23.8 |
30.0 |
22.8 |
20.3 |
35.5 |
|||||||
|
Primary Use: Internet |
||||||||||||
|
14.0 |
12.5 |
16.4 |
11.9 |
9.9 |
3.1 |
|||||||
|
5.4 |
11.0 |
15.2 |
4.0 |
4.7 |
||||||||
a. Formulate hypotheses about the two population variances
that can be used to determine whether the population variance in battery life
is greater for the talk time application. Consider the talk time use as
population and Internet use as population .
b. What are the standard deviations of battery life
for the two samples (to decimals)?
c. Conduct the hypothesis test and compute the -value.
p-value
= (to
decimals)
Using a
level of significance, what is your conclusion?
. We
that
the population variance in battery hours of use for the talk time application
is larger than the population variance in battery hours of use for the Internet
application.
Question 6
According
to the Corporate Travel Index compiled by Business Travel News, the
average daily cost for business travel in the United States rose to per day (Executive
Travel website). The file Travel contains sample data
for an analogous study on the estimated daily living costs for an executive
traveling to various international cities. The estimates include a single room
at a four-star hotel, beverages, breakfast, taxi fares, and incidental costs.
Click on the datafile logo to reference the data.
|
City |
Daily Living
Cost ($) |
City |
Daily Living
Cost ($) |
|
Bangkok |
242.87 |
Mexico City |
212.00 |
|
Bogota |
260.93 |
Milan |
284.08 |
|
Cairo |
194.19 |
Mumbai |
139.16 |
|
Dublin |
260.76 |
Paris |
436.72 |
|
Frankfurt |
355.36 |
Rio de Janeiro |
240.87 |
|
Hong Kong |
346.32 |
Seoul |
310.41 |
|
Johannesburg |
165.37 |
Tel Aviv |
223.73 |
|
Lima |
250.08 |
Toronto |
181.25 |
|
London |
326.76 |
Warsaw |
238.20 |
|
Madrid |
283.56 |
Washington, D.C. |
250.61 |
a. Compute the sample mean (to decimals).
b. Compute the sample standard deviation (to
decimals).
c. Compute a confidence interval for the population
standard deviation (to decimals). Use Table
11.1.
( , )
Question 7
Is
there any difference in the variability in golf scores for players on the LPGA
Tour (the women's professional golf tour) and players on the PGA Tour (the
men's professional golf tour)? A sample of tournament scores from LPGA events
showed a standard deviation of strokes, and a sample of tournament scores from
PGA events showed a standard deviation of . Conduct a hypothesis test for equal
population variances to determine whether there is any statistically
significant difference in the variability of golf scores for male and female
professional golfers. Use .
What is your conclusion?
There
is
significant
difference in the variances.
Question
8
Stable
cost reporting in a manufacturing setting is typically a sign that operations
are running smoothly. The accounting department at Rockwell Collins, an
avionics manufacturer, analyzes the variance of the weekly costs reported by
two of its production departments. A sample of cost reports for each of the two
departments shows cost variances of and , respectively. Is this sample
sufficient to conclude that the two production departments differ in terms of
unit cost variance? Use (to decimals).
Ashford BUS308 Week 4 Discussion
ANOVA: Case Problem Touristopia Travel [WLOs: 1,
2, 3] [CLOs: 1, 2, 3, 4, 5, 6, 7].
Prior to beginning work on this discussion forum,
watch the Week 4 Introduction (Links to an external site.) video, and read Chapter 13 in the
MindTap ebook by clicking on the Getting Ready link for each
perspective chapter.
Step 1: Read:
·
Review Case
Problem 3: TourisTopia Travel download from Chapter 13 in the ebook.
Step 2: Do:
·
Run the ANOVA:
Two-Factor with Replication statistics for the Data File TourisTopia
(Chapter 13) using the video How to Add Excel's Data Analysis
ToolPak (Links to an external site.) for assistance.
In a managerial report,
·
Use descriptive statistics
to summarize the data from Triple T's study. Based on descriptive statistics,
what are your preliminary conclusions about whether the time spent by visitors
to the Triple T website differs by background color or font? What are your
preliminary conclusions about whether time spent by visitors to the Triple T
website differs by different combinations of background color and font?
·
Explain whether Triple
T has used an observational study or a controlled experiment.
·
Use the data from
Triple T's study to test the hypothesis that the time spent by visitors to the
Triple T website is equal for the three background colors. Include both factors
and their interaction in the ANOVA model, and use a=.05.
·
Use the data from Triple
T's study to test the hypothesis that the time spent by visitors to the Triple
T website is equal for the three fonts. Include both factors and their
interaction in the ANOVA model, and use a=.05.
·
Use the data from
Triple T's study to test the hypothesis that time spent by visitors to the
Triple T website is equal for the nine combinations of background color and
font. Include both factors and their interaction in the ANOVA model, and use
a=.05.
·
Discuss whether the
results of your analysis of the data provide evidence that the time spent by
visitors to the Triple T website differs by background color, font, or
combination of background color and font. What is your recommendation?
Step 3: Discuss:
·
What recommendations
does your ANOVA results support? Use findings from your managerial report to
support your recommendations. Be sure to include why you support certain
decisions over others. What surprising findings did you come up with during
your analysis?
Ashford
BUS308 Week 4 Chapter 13 Assignment
Question
1
Exercise 13.11 (Analysis of Variance and the
Completely Randomized Design)
How long it takes paint to dry can have an
impact on the production capacity of a business. In May , Deal's Auto Body
& Paint in Prescott, Arizona, invested in a paint-drying robot to speed up
its process (The Daily Courier website, https://www.dcourier.com/photos/2018/may/26/984960336/). An interesting question is, "Do all
paint-drying robots have the same drying time?" To test this, suppose we
sample five drying times for each of different brands of paint-drying robots.
The time in minutes until the paint was dry enough for a second coat to be
applied was recorded. The following data were obtained.
Click on the datafile logo to reference the
data.
|
Robot 1 |
Robot 2 |
Robot 3 |
Robot 4 |
|
128 |
144 |
133 |
150 |
|
137 |
133 |
143 |
142 |
|
135 |
142 |
137 |
135 |
|
124 |
146 |
136 |
140 |
|
141 |
130 |
131 |
153 |
At the level of significance, test to see
whether the mean drying time is the same for each brand of robot.
Compute the values identified below (to
decimals, if necessary).
|
Sum of Squares, Treatment |
|
|
Sum of Squares, Error |
|
|
Mean Squares, Treatment |
|
|
Mean Squares, Error |
|
Calculate the value of the test statistic (to
decimals).
The -value is
What is your
conclusion?
Question
2
Exercise 13.15 Algo
(Multiple Comparison Procedures)
To test whether the mean time needed to mix a
batch of material is the same for machines produced by three manufacturers, the
Jacobs Chemical Company obtained the following data on the time (in minutes)
needed to mix the material.
|
Manufacturer |
||||
|
1 |
2 |
3 |
||
|
17 |
28 |
23 |
||
|
23 |
26 |
22 |
||
|
21 |
31 |
26 |
||
|
19 |
27 |
25 |
||
a. Use these data to test whether the population mean times
for mixing a batch of material differ for the three manufacturers. Use .
Compute the values below (to decimals, if necessary).
|
Sum of Squares, Treatment |
|
|
Sum of Squares, Error |
|
|
Mean Squares, Treatment |
|
|
Mean Squares, Error |
|
Calculate the value of the test statistic (to
decimals).
The -value is
What is your
conclusion?
b. At the level of significance, use Fisher's LSD procedure
to test for the equality of the means for manufacturers and .
Calculate Fisher's LSD Value (to decimals).
What conclusion can you draw after carrying
out this test?
Question
3
In the digital age of marketing, special care
must be taken to ensure that programmatic ads appear on websites aligned with a
company's strategy, culture, and ethics. For example, in , Nordstrom, Amazon,
and Whole Foods each faced boycotts from social media users when automated ads
for these companies showed up on the Breitbart website (ChiefMarketer.com website).
It is important for marketing professionals to understand a company's values
and culture. The following data are from an experiment designed to investigate
the perception of corporate ethical values among individuals specializing in
marketing (higher scores indicate higher ethical values).
|
Marketing
Managers |
Marketing Research |
Advertising |
|
6 |
5 |
6 |
|
5 |
5 |
7 |
|
4 |
4 |
6 |
|
5 |
4 |
5 |
|
6 |
5 |
6 |
|
4 |
4 |
6 |
a. Use to test for a significant difference in perception among the
three groups.
Compute the values identified below (to
decimals, if necessary).
|
Sum of Squares, Treatment |
|
|
Sum of Squares, Error |
|
|
Mean Squares, Treatment |
|
|
Mean Squares, Error |
|
Calculate the value of the test statistic (to
decimals).
The -value is
What is your conclusion?
b. Using , determine where differences between the mean perception
scores occur.
Calculate Fisher's LSD value (to decimals).
Test whether there is a significant difference
between the means for marketing managers ( ), marketing research specialists (
), and advertising specialists ( ).
|
Absolute Value |
||
|
Difference |
(to decimal) |
Conclusion |
Question
4
n experiment has been conducted for four
treatments with eight blocks. Complete the following analysis of variance table
(to decimals but p-value to decimals, if necessary). If answer is
zero enter " ".
|
Source |
Sum |
Degrees |
Mean |
||
|
of Variation |
of Squares |
of Freedom |
Square |
-value |
|
|
Treatments |
|
|
|
|
|
|
Blocks |
|
|
|
||
|
Error |
|
|
|
|
|
|
Total |
|
|
|
Use to test for any significant differences.
The -value is
What is your
conclusion?
Question
5
Are there differences in airfare depending on
which travel agency website you utilize? The following data were collected on
travel agency websites on July , . The following table contains the prices in
U.S. dollars for a one-way ticket between the cities listed on the left for
each of the three travel agency websites. Here the pairs of cities are the
blocks and the treatments are the different websites.
Click on the datafile logo to reference the
data.
|
Websites |
||||||
|
Flight From ‒ To |
Expedia ($) |
TripAdvisor ($) |
Priceline ($) |
|||
|
Atlanta to Seattle |
176.00 |
166.00 |
175.80 |
|||
|
New York to Los Angeles |
195.00 |
195.00 |
206.20 |
|||
|
Cleveland to Orlando |
77.00 |
72.00 |
76.21 |
|||
|
Dallas to Indianapolis |
149.00 |
149.00 |
148.20 |
|||
Use to test for any significant differences in the mean price of a
one-way airline ticket for the three travel agency websites. If your answer is
zero, enter " ".
|
Source |
SS |
MS |
F |
P-value |
F crit |
|
|
of variation |
(to decimals) |
df |
(to decimals) |
(to decimals) |
(to decimals) |
(to decimals) |
|
Trip |
|
|
|
|
|
|
|
Website |
|
|
|
|
|
|
|
Error |
|
|
|
|||
|
Total |
|
|
The -value corresponding to Website is
.
What is your conclusion?
We
the null hypothesis that there is no
difference in price among the three websites.
Question
6
A study reported in The Accounting
Review examined the separate and joint effects of two levels of time
pressure (low and moderate) and three levels of knowledge (naive, declarative,
and procedural) on key word selection behavior in tax research. Subjects were
given a tax case containing a set of facts, a tax issue, and a key word index
consisting of key words. They were asked to select the key words they believed
would refer them to a tax authority relevant to resolving the tax case. Prior
to the experiment, a group of tax experts determined that the text contained
relevant key words. Subjects in the naive group had little or no declarative or
procedural knowledge, subjects in the declarative group had significant
declarative knowledge but little or no procedural knowledge, and subjects in
the procedural group had significant declarative knowledge and procedural
knowledge. Declarative knowledge consists of knowledge of both the applicable
tax rules and the technical terms used to describe such rules. Procedural
knowledge is knowledge of the rules that guide the tax researcher's search for
relevant key words. Subjects in the low time pressure situation were told they
had minutes to complete the problem, an amount of time which should be
"more than adequate" to complete the case; subjects in the moderate
time pressure situation were told they would have "only" minutes to
complete the case. Suppose subjects were selected for each of the six treatment
combinations and the sample means for each treatment combination are as follows
(standard deviations are in parentheses).
Excel File: data13-33.xlsx
|
|
Knowledge |
|||
|
|
Naive |
Declarative |
Procedural |
|
|
|
Low |
1.13 |
1.56 |
2.00 |
|
Time Pressure |
||||
|
|
||||
|
Moderate |
0.48 |
1.68 |
2.86 |
|
Use the ANOVA procedure to test for any
significant differences due to time pressure, knowledge, and interaction. Use a
level of significance. Assume that the total sum of squares for this experiment
is
Letting Time Pressure be Factor A and
Knowledge be Factor B, show the entries in the ANOVA table (to decimals, if
necessary). Do not round intermediate calculations. If your answer is zero,
enter "0".
|
Source of Variation |
Sum |
Degrees |
Mean Square |
F |
p-value |
|
Factor A |
|
|
|
|
|
|
Factor B |
|
|
|
|
|
|
Interaction |
|
|
|
|
|
|
Error |
|
|
|
|
|
|
Total |
|
|
|
The -value for Factor A is
What is your conclusion with respect to Factor
A?
The -value for Factor B is
What is your conclusion with respect to Factor
B?
The -value for the interaction of factors A
and B is
What is your conclusion with respect to the
interaction of Factors A and B?
Question
7
A Pew Research study conducted in found that
approximately of Americans believe that robots and computers might one day do
many of the jobs currently done by people (Pew Research website, http://www.pewinternet.org/2017/10/04/americans-attitudes-toward-a-future-in-which-robots-and-computers-can-do-many-human-jobs/). Suppose we have the following data
collected from nurses, tax auditors, and fast-food workers in which a higher
score means the person feels his or her job is more likely to be automated.
|
Tax |
Fast-Food |
|
|
Nurse |
Auditor |
Worker |
|
4 |
4 |
5 |
|
5 |
5 |
7 |
|
5 |
4 |
6 |
|
3 |
6 |
4 |
|
3 |
6 |
5 |
|
5 |
5 |
6 |
|
6 |
6 |
5 |
|
5 |
6 |
8 |
a. Use to test for differences in the belief that a person's
job is likely to be automated for the three professions.
(to
decimals)
The -value is
.
What is your conclusion?
We
the null hypothesis that the mean scores are
the same for the three professions.
b. Use Fisher's LSD procedure to compare the belief that a
person's job will be automated for nurses and tax auditors.
(to
decimals)
What is your conclusion?
We
the null hypothesis that the two population
means are equal.
Question
8
A factorial experiment was designed to test
for any significant differences in the time needed to perform English to
foreign language translations with two computerized language translators.
Because the type of language translated was also considered a significant factor,
translations were made with both systems for three different languages:
Spanish, French, and German. Use the following data for translation time in
hours.
|
Language |
|||
|
Spanish |
French |
German |
|
|
System 1 |
6 |
14 |
15 |
|
10 |
18 |
19 |
|
|
System 2 |
10 |
12 |
14 |
|
14 |
14 |
20 |
|
Test for any significant differences due to
language translator system (Factor A), type of language (Factor B), and
interaction. Use .
Complete the following ANOVA table (to
decimals, if necessary). Round your p-value to decimal places.
|
Source of Variation |
Sum of Squares |
Degrees of Freedom |
Mean Square |
F |
p-value |
|
Factor A |
|
|
|
|
|
|
Factor B |
|
|
|
|
|
|
Interaction |
|
|
|
|
|
|
Error |
|
|
|
||
|
Total |
|
|
The p-value for Factor A is
What is your conclusion with respect to Factor
A?
The p-value for Factor B is
What is your conclusion with respect to Factor
B?
The p-value for the interaction of
factors A and B is
What is your conclusion with respect to the
interaction of Factors A and B?
Ashford BUS308 Week 5 Discussion Case Problem
Predicting Winnings for NASCAR Drivers
Multiple Regression: Case Problem Predicting
Winnings for NASCAR Drivers [WLOs: 1, 2, 3] [CLOs: 1, 2, 3, 4, 5, 6, 7]
Prior to beginning work on this discussion
forum, watch the Week 5 Introduction (Links to an external site.) video, and read Chapter 15 in the
MindTap ebook by clicking on the Getting Ready link for each
perspective chapter.
Step 1: Read
·
Review Case
Problem 2: Predicting Winnings for NASCAR Drivers download from Chapter 15 of the ebook.
Step 2: Do
·
Run a Regression for
the Data File NASCAR (Chapter 15) using the video How to Add Excel's Data Analysis
ToolPak (Links to an external site.) for assistance.
In a managerial report,
·
Suppose you wanted to
predict Winnings ($) using only the number of poles won (Poles), the number of
wins (Wins), the number of top five finishes (Top 5), or the number of top ten
finishes (Top 10). Which of these four variables provides the best single
predictor of winnings?
·
Develop an estimated
regression equation that can be used to predict Winnings ($) given the number
of poles won (Poles), the number of wins (Wins), the number of top five
finishes (Top 5), and the number of top ten (Top 10) finishes. Test for
individual significance, and then discuss your findings and conclusions.
Step 3: Discuss:
·
What did you find in
your analysis of the data? Were there any surprising results? What
recommendations would you make based on your findings? Include details from
your managerial report to support your recommendations.
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