Assignment 2: Using Descriptive Statistics

In the news, we are constantly bombarded by statistics such as unemployment rates, stock market swings, or changes in the housing market. A vast majority of the statistical information presented to us is in the form of descriptive statistics. In descriptive statistics, a sample is taken, and values such as mean, median, mode, standard deviation, and variance are determined. These values are used to compare to other samples or are used as a measure of the current state of a population. The use of descriptive statistics is a common practice in the decision-making process in many professional fields.

In this assignment, you will use descriptive statistics to make an informed decision—in this case, to decide whether you are going to purchase a new car. Consider the following scenario:

The manufacturer claims that the Brillton EX gets 25 miles per gallon (MPG) in the city and 35 MPG on the highway. However, you are skeptical. You manage to retrieve data for the first Brillton EX models that were tested by a consumer protection agency. This data is available in the following spreadsheet. Click here to review the Excel spreadsheet.

This spreadsheet consists of several tabs:

• Samples: This tab contains all of the different samples tested. These are randomly selected Brillton EX cars. The MPG levels of these cars were measured in the city and on the highway.
• Descriptive Statistics: This tab contains the formulas that will calculate the mean, median, mode, standard deviation, and variance from the sample data.
• Population: This tab contains the mean, median, mode, standard deviation, and variance for the entire population of Brillton EX models.

Instructions:

• Download the Brillton EX spreadsheet.
• On the Samples tab, chose one of the data samples.
• Input the data from the sample you selected into the Sample Data columns on the Descriptive Statistics tab. When you are done, the spreadsheet will automatically determine the mean, median, mode, standard deviation, and variance for this sample.
  Note: There is a tab labeled Example to show you how this should work if done properly.
• In your report, address the following:
• Report the sample name that you selected.
• Report the mean, median, mode, standard deviation, and variance that were calculated for your sample. What does each of these values represent with respect to your sample?
• Compare the descriptive statistics you calculated to the population statistics reported. Were there differences? Why or why not?
• Do you think that the sample you picked was representative of the population? Explain your response.
• Do you think that using descriptive statistics is a reliable method for gathering data in order to make an informed decision?
• Based upon your analysis, do you accept the manufacturer’s claim that the Brillton EX gets 25 MPG in the city and 35 MPG on the highway? Why or why not?

For this assignment, submit a summary of your responses to the questions above in a 1–3-page Word document. Apply APA standards to citation of sources. Name your Word document as follows: LastnameFirstInitial_M2_A2.doc. Submit it to the M2: Assignment 2 Dropbox by Wednesday, March 4, 2015.

Grading Criteria and Rubric