Gas Price Test
AAA reported that the average price of regular gasoline in California during the third week of October 2025 was $4.62 per gallon (gasprices.aaa.com/?state=CA). The data in the Excel sheet linked below show the price per gallon of regular gasoline for 30 randomly selected stations in Orange county. Do the results from the sample indicate that the average Orange county gas price is lower than the state average? Explain.
Orange County Gas Prices – October 2025.xlsx Download Orange County Gas Prices – October 2025.xlsx
- Calculate the mean and standard deviation of the sample – show your calculations. Give an explanation as to what this means in relation to this problem. In other words, how would you explain what these numbers mean to someone who does not understand statistics?
- Calculate the first, second, and third quartiles as well as the interquartile range – show your calculations. Give an explanation as to what this means in relation to this problem.
- Construct the 95% confidence interval to 2 decimal places (make sure to include whether you used z or t) – show your calculations. Give an explanation as to what this means in relation to this problem.
- Describe the similarities and differences between the interquartile range and confidence interval calculated.
- Formulate your null and alternative hypotheses.
- Assume a level of significance of α = 0.05.
- Calculate the test statistic. Be sure to include whether you used z or t.
- Calculate either the critical value or the p-value.
- Do the results of your hypothesis test indicate that the average Orange county gas price is lower than the state average? Be sure to address how your results from the above analyses lead to your decision to either reject or fail to reject your null hypothesis.
Use at least one reference (open resource, newspaper, or textbook).
Formatting Guidelines
- 12-point Times New Roman font
- Double-spaced
- 1-inch margins
- An APA running head – shortened title, all caps limited to 50 characters, in the upper left corner of each page
- Page number at the top right of each page
- A title page with the paper’s title (no more than 12 words in length), your name, professor’s name, department, and the name of the university.
-
• Do the results from the sample indicate that the average Orange county gas price is lower than the state average? Explain.,
-
• Calculate the mean and standard deviation of the sample – show your calculations. Give an explanation as to what this means in relation to this problem. In other words, how would you explain what these numbers mean to someone who does not understand statistics?,
-
• Calculate the first second and third quartiles as well as the interquartile range – show your calculations. Give an explanation as to what this means in relation to this problem.,
-
• Construct the 95% confidence interval to 2 decimal places (make sure to include whether you used z or t) – show your calculations. Give an explanation as to what this means in relation to this problem.,
-
• Formulate your null and alternative hypotheses.