Practical Application Scenario

To complete this scenario, use the Confidence Interval Calculator and the Area Gas Prices %u2013 Random Sample documents, provided in the Resources.

The Minneapolis Star Tribune newspaper has decided to write an article about gasoline prices in the Twin Cities area (Minneapolis and St. Paul). The Star Tribune has designed a survey and taken a simple random sample of regular unleaded gas prices at 70 area stations. The results are in the Area Gas Prices %u2013 Random Sample file. The Star Tribune's policy is that no data will be reported unless they are 95 percent confident that the numbers are correct. As the new manager of the data verification unit at the Star Tribune, you need to develop a 95 percent confidence interval for the average price of regular unleaded gasoline in the area.

You already know how to compute sample parameters like the sample mean and sample standard deviation; this scenario simply asks you to complete a confidence interval for the data provided above and communicate the results to the Star Tribune's business manager