Chapter 8 Case Study: Motor Vehicle Fuel Efficiency.
Use the following information for Exercises 69–74. The Environmental Protection Agency calculates the estimated annual fuel cost for motor vehicles, with the resulting data provided in the variable annual fuel cost of the Chapter 8 Case Study data set Fuel Efficiency. A sample of the annual fuel cost is provided for 12 vehicles.
| Annual fuel cost | |||
|---|---|---|---|
| 1750 | 2500 | 2400 | 2350 |
| 2150 | 3100 | 2950 | 2500 |
| 2550 | 2750 | 2300 | 2800 |
Question 8.170
73. Construct and interpret a 90% confidence interval for the population mean annual fuel cost.
8.2.73
(2318.2, 2697.8). We are 90% confident that μ, the population mean annual fuel cost, lies between $2318.2 and $2697.8.