Minitab Assignment
Project: Averages and Variations In July of 2010, two reporters writing for the Los Angeles Times broke a story about the city of Bell, one of the poorest and smallest cities in Los Angeles County. The two highest paid city officials, Manager Robert Rizzo and Assistant City Manager Angela Spaccia, pulled in salaries that seemed much higher than similar officials working in much larger, wealthier cities in the United States. Further investigation uncovered many instances of corruption among several of the city managers and city leaders, including instances of council members being paid thousands of dollars to attend meetings that lasted no longer than a few minutes. Preliminary Hearing of Bell City Manager Robert Rizzo In this project, you will do the following. · Compute the mean and median to get a sense of how much a typical public employee earns in these cities. · Calculate the standard deviation, and determine how much variation there is in public employee salaries. · Look for any extreme outliers in public employee salaries, using the standard deviation. Data: For this project, you need to download the bellemployeesalaries.csv dataset. The data comes from the California State Controller's database, which contains information on the salary and other compensation benefits of public employees in the cities, counties, and special districts of California. The data you will be using shows the 2009 salaries of paid public employees (working more than 25 hours per week) for the cities of Bell and Duarte. Each row in the file represents a paid public employee. The file contains four columns: · cityName—the name of the city where the employee works; in this data file, the city will be either Bell or Duarte · department—the department name where the city employee worked · position—the job title of the city employee · wages—the total amount the employee earned in the year 2009 in US dollars, including their base pay and overtime Questions: 1. Create and upload a histogram of the salary data for the city of Bell, where each bar width is about 50,000 US dollars. Is the distribution of the salaries symmetric? Why/Why not? 2. Without making any calculations, will the mean be larger or smaller than the median? Explain why. 3. For the city of Duarte, the median salary is 31,597.00 US dollars, the mean salary is 44,713.88 US dollars, and the standard deviation of the salaries is 36,448.59 US dollars (using the formula for the population standard deviation—recall that the data contains the salaries of all city employees). What is the population median, mean, and standard deviation for the salaries in Bell? (Round your answers to two decimal places.) You can use computer to calculate these statistic. Compare the mean salaries of Bell and Duarte, paying attention to the position titles and salaries in the two cities. Does it pay to be a police officer in Bell? 4. In general, city managers earn the highest salaries in a city, and are paid well above a typical city employee. We want to find how far away the city manager salaries are from the mean for each city. Some cities have more variation in salaries than others, so we will compute how far the highest paid salaries are from the mean, and then divide that difference by the standard deviation of the city salaries, in order to make a fair comparison. In other words, we are going to calculate how many standard deviations the highest salaries are from their city means. Use the following formula. (Highest Salary − Mean Salary) Standard Deviation 5. For the city of Bell, how many standard deviations is the highest salary from the mean? 6. For the city of Duarte, how many standard deviations is the highest salary from the mean? 7. As an investigative reporter, you are used to seeing city manager salaries 4 or even 5 standard deviations away from the mean. What do you find curious about this data?