For Exercises 23–35, do the following:

  1. Provide the null and alternative hypotheses.
  2. Describe the two ways a correct decision could be made in the context of the problem.
  3. Describe what a Type I error would mean in the context of the problem.
  4. Describe what a Type II error would mean in the context of the problem.

Question 9.25

25. Hybrid Vehicles. The motor vehicle Web site Edmunds.com wants to test whether owners of hybrid vehicles can recoup their initial increased cost through reduced fuel consumption in less than three years, on average.

9.1.25

(a) versus (b) Conclude that the population mean number years it takes for owners of hybrid vehicles to recoup their initial increased cost through reduced fuel consumption is less than 3 years when, in reality, it is less than 3 years. Conclude that the population mean number years it takes for owners of hybrid vehicles to recoup their initial increased cost through reduced fuel consumption is equal to 3 years when, in reality, it is equal to 3 years. (c) Conclude that the population mean number years it takes for owners of hybrid vehicles to recoup their initial increased cost through reduced fuel consumption is less than 3 years when, in reality, it is equal to 3 years. (d) Conclude that the population mean number years it takes for owners of hybrid vehicles to recoup their initial increased cost through reduced fuel consumption is equal to 3 years when, in reality, it is less than 3 years.