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Competency Given a real-life application, develop a confidence interval for a population parameter and its interpretation

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Competency
Given a real-life application, develop a confidence interval for a
population parameter and its interpretation.
Instructions
Scenario (information repeated for deliverable 01, 03, and 04)
A major client of your company is interested in the salary
distributions of jobs in the state of Minnesota that range from
$30,000 to $200,000 per year. As a Business Analyst, your boss
asks you to research and analyze the salary distributions. You are
given a spreadsheet
that contains the following information: |
e A listing of the jobs by title
e The salary (in dollars) for each job
You have previously explained some of the basic statistics to your
client already, and he really liked your work. Now he wants you to
analyze the confidence intervals.
Background information on the Data
The data set in the spreadsheet consists of 364 records that you

e A listing of the jobs by title

¢ The salary (in dollars) for each job
You have previously explained some of the basic statistics to your
client already, and he really liked your work. Now he wants you to
analyze the confidence intervals.
Background information on the Data
The data set in the spreadsheet consists of 364 records that you
will be analyzing from the Bureau of Labor Statistics. The data set
contains a listing of several jobs titles with yearly salaries ranging
from approximately $30,000 to $200,000 for the state of
Minnesota.
What to Submit
Your boss wants you to submit the spreadsheet with the
completed calculations. Your research and analysis should be
present within the answers provided on the worksheet.
Grading Rubric

Not Did not : Correctly solved a j Correctly solved , All problems
Submitted correctly solve : majority of the almost all the ; are solved
| a majority of : problems, problems. correctly.
the problems
or at least one : :
problem left
| blank. |
Not Very few Fairly complete and | Mostly complete : Complete and
| Submitted steps are ? detailed steps are and detailed | detailed steps
| provided to ) provided to explain | steps are : are provided
explain how | how to solve the | provided to 2 to explain

| to solve the : problem OR the explain how to | how to solve
problem OR steps provided have solve the | the problem. |
| the steps some errors. | — problem.

provided to provided to explain steps are are provided
7 | explain how how to solve the provided to : toexplain |
to solve the problem OR the | explain how to how to solve |
problem OR steps provided have solve the the problem.
the steps some errors. problem. | :
provided have
several
errors. | |
Not | Explanations Explanations Explanations Explanations
Submitted | generally lack | demonstrate abasic} demonstrate a | demonstrate
| | i
a basic understanding of proficient | a mastery of

| understanding most of the | understanding understanding |
7 of the Statistical concepts of most of the of the )
| Statistical and terminology, but statistical statistical

concepts or some explanations ;| concepts and | concepts and :

lack of proper may be incomplete terminology, but terminology.

Here are some hints for Deliverable 3 from the Assessors: "
please emphasize the following:
1. D3 uses the same dataset in D1, so the students do not need to recalculate the mean and standard
deviation. :
2. They need to refer to the calculated mean and standard deviation values from D1 in their
confidence interval calculations. They should not be manually typing in the mean or standard
https:/Aearning.rasmussen.edu/ultra/courses/_73930_1/cl/outline 1
40/20/2020 View Message — STA3215CBE Section 02CBE Inferential ...
deviation values. |
3. Because of cell referencing, they should not be rounding any values in the spreadsheet. In their
answers in the Word document, they can round to either cents or dollars.
4. In Q4, they need to provide a numerical example that clearly shows an unpractical use of the 99%
confidence interval.
5. Q5, they need to say why 364 is large enough

Deliverable 03 Worksheet
1. Discuss the importance of constructing confidence intervals for the population mean by answering
these questions.
o What are confidence intervals?
o What ts a point estimate?
o What is the best point estimate for the population mean? Explain.
o Why do we need confidence intervals?
Answer and Explanation:
Enter your step-by-step answer and explanations here.

2. Using the data from the Excel workbook, construct a 95% confidence interval for the population
mean. Assume that your data is normally distributed and o is unknown. Include a statement that
correctly interprets the confidence interval in context of the scenario.

Hint: Use the sample mean and sample standard deviation from Deliverable 1.
Answer and Explanation:

Enter your step-by-step answer and explanations here.

3. Using the data from the Excel workbook, construct a 99% confidence interval for the population
mean. Assume that your data is normally distributed and o is unknown. Include a statement that
correctly interprets the confidence interval in context of the scenario.

Hint: Use the sample mean and sample standard deviation from Deliverable 1.
Answer and Explanation:
Enter your step-by-step answer and explanations here.

4. Compare your answers for (2) and (3). You notice that the 99% confidence interval is wider. What
is the advantage of using a wider confidence interval? Why would you not always use the 99%
confidence interval? Explain with an example.

Answer and Explanation:
Enter your step-by-step answer and explanations here.

5. We want to estimate the mean salary in Minnesota. How many jobs must be randomly selected for
their respective mean salaries if we want 95% confidence that the sample mean is within $126 of the
population mean and o = $1150,

Is the current sample size of 364 in the data set in our Excel workbook large enough? Explain.
Answer and Explanation:
Enter your step-by-step answer and explanations here.