Deliverable 3 – Confidence Intervals

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:

• 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.

Student’s name

Deliverable 01 Worksheet

1. Introduce your scenario and data set.

· Provide a brief overview of the scenario you are given and describe the data set.

· Describe how you will be analyzing the data set.

· Classify the variables in your data set.

· Which variables are quantitative/qualitative?

· If it is a quantitative variable, is it discrete or continuous?

· Describe the level of measurement for each variable included in the data set (nominal, ordinal, interval, ratio).

Answer and Explanation:

 

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

The scenario is about analyzing salary distribution in Minnesota. The data set contains several jobs with salaries ranging from $30,000 to $200,000. It contains 364 records from the Bureau of Statistics that need to be analyzed.

The data set will be analyzed through measures of central tendencies such as the mode, mean, and median.

Quantitative variables are the salary ranges.

The level of measurement will be interval scale. Mode, median or mean are helpful in calculating central tendency in the interval scale.

 

 

 

 

 

 

 

 

 

2. Discuss the importance of the Measures of Center.

· Name and describe each measure of center.

· Discuss the advantages and/or disadvantages of each.

Answer and Explanation:

 

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

The three measures of center are; mode, mean and median. Mean is the average found by adding together values in data and dividing that sum by the total number of data items.

Median is the middle value of data that is arranged in an orderly manner.

Mode is the most appearing data value in a data set.

The mean and median give a picture of the middle of the data set. In this scenario, they give middle of job salaries in Minnesota; the mean is $71,879 and median is $66,525.

The mode is $71, 420 meaning that some jobs had the same salaries.

 

 

 

3. Discuss the importance of the Measures of Variation.

· Name and describe each measure of variation.

· Discuss the advantages and/or disadvantages of each.

Answer and Explanation:

 

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

The variance is simply the way data is spread out or dispersed. It is useful in calculating standard deviation.

The standard deviation is simply the average deviation from the mean. It expresses the difference of a data set from the mean value of the data set.

 

 

 

4. Calculate the measures of center and measures of variation from the data set and list them below. Be sure to include (a)aninterpretationof each measure in context of the scenario(for example, if the median is larger than the mean, what does it mean? What does the value of standard deviation tell you?) and (b) correct units of measurement. Show your calculations in your spreadsheet. You do not need to include Excel functions in your written answer below.

· Mean

· Median

· Mode

· Midrange

· Range

· Variance

· Standard deviation

 

Answer and Explanation:

 

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

Mean = Total Salary of Jobs/364

=$71,879

Median = Mean of the two middle Numbers

It is obtained by arranging the values in order then finding the average between the 182 and 183 values. From the excel chart it is $66,525.

Mode is the number appearing most which is $71,420

Midrange it is obtained by finding the maximum of the data set adding to the minimum of the data set and dividing by 2.

Range it is obtained by subtracting the minimum of the data set from the maximum of the data set. In this case it is $167,760

Variance is 5.46E+08

Standard deviation is 23367.36018

 

 

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