Question 9.434

11. Alcohol-Related Fatal Car Accidents. The National Traffic Highway Safety Commission keeps statistics on the “mean years of potential life lost” in alcohol-related fatal automobile accidents. For males, the mean years of life lost is 32. That is, on average, males involved in fatal drinking-and-driving accidents had their lives cut short by 32 years. A random sample of 36 alcohol-related fatal accidents had a mean years of life lost of 33.8, with a standard deviation of 6 years.

  1. Test whether the population mean years of life lost has changed, using a test and level of significance .
  2. Assess the strength of the evidence against the null hypothesis.