Companies often develop and test hypotheses about their products. For example, car manufacturers will test their cars to determine fuel efficiency and miles
per gallon. To ensure that products are safe and that they perform as advertised, regulatory and consumer protection groups also test companies’ claims.
For this Assignment, you are working at a firm that conducts independent testing for heavy industry. Recently, an automobile manufacturer has been in the
news for complaints about the highway gas mileage of their latest model minivan. You receive a contract from a consumer action group to test and write a
report on the company’s claim that its minivans get 28 miles per gallon on the highway. The car company agrees to allow you to select randomly 35 lowmileage fleet minivans to test their highway mileage. Your test results gave you the following data:
29.7 24.5 27.1 29.8 29.2 27.0 27.8 24.1 29.3
25.9 26.2 24.5 32.8 26.8 27.8 24.0 23.6 29.2
26.5 27.7 27.1 23.7 24.1 27.2 25.9 26.7 27.8
27.3 27.6 22.8 25.3 26.6 26.4 27.1 26.1
To prepare for this Assignment:
Review this week’s Learning Resources.
Refer to the scenario above and the data that was provided by the car company.
Refer to the Academic Writing Expectations for 2000/3000-Level Courses as you compose your Assignment.
By Day 7
Submit Part 1 of your report according to the following prompts.
Part 1: Sample Mean, Standard Deviation, and Confidence Interval
Complete the following and include your results and responses in your report:
Include a brief introduction that provides a context for the assignment you have been given by your firm.
Calculate a 95% confidence interval around your sample mean. (75 words, or 1 paragraph)
Note: Include your calculations. If your calculations are submitted separately, make note of where they can be found.
Is the company’s claimed mean inside your confidence interval? (75 words, or 1 paragraph)
What does that result indicate about the company’s claim? (75 words, or 1 paragraph)
Note: For each prompt, be sure to reference at least one scholarly source to support your answer
Part 2
Part 2: Hypothesis Testing: Two-Tail Test and One-Tail Test
Complete the following and include your results and responses in your report (use alpha = 0.05):
List the null and alternative hypotheses for the two-tail test for the mean. Calculate the observed value of the test statistic and the associated p-value. (75– 150 words, or 1–2 paragraphs)
Is the observed test statistic in the critical region? Is the p-value higher or lower than your alpha? (75–150 words, or 1–2 paragraphs)
Note: Include your calculations. If your calculations are submitted separately, make note of where they can be found.
List the null and alternative hypotheses for the one-tail test of the mean. Calculate the observed value of the test statistic and the associated p-value. (75– 150 words, or 1–2 paragraphs)
Is the observed test statistic in the critical region? Will the p-value be higher or lower than your alpha? (75–150 words, or 1–2 paragraphs)
Note: Include your calculations. If your calculations are submitted separately, make note of where they can be found
Conclusions
In your report, use the confidence interval information and the results of the hypothesis testing to provide support for your conclusions and recommendations to the company. Specifically:
What conclusions did you reach? What did you learn about the situation by using each method? Did one method offer more conclusive proof than another? (150–225 words, or 2–3 paragraphs)
Based on your results, do you support the company’s claim that their minivans get 28 miles per gallon? (75 words, or 1 paragraph)
Summarize the details of your test methods and the results from each statistical method you used. Explain the findings so that executives from both the agency and the company can understand your conclusion. (150–225 words, or 2–3 paragraphs)
Finally, present recommendations for actions that the company might take to use your findings to better serve their customers in the future. (75 words, or 1 paragraph)
