The police department of a major city reports that the mean number of auto thefts per neighborhood per year is ( m ) 6.88 with a standard deviation (s ) of 1.19. As the mayor of a suburban community just outside the major city, you're curious as to how the auto theft rate in your community compares. You determine that the mean ( X ) number of auto thefts per neighborhood per year for a random sample of 15 neighborhoods in your community is 8.13. Assume that you're working at the .05 level of signi?cance.
a. State an appropriate null hypothesis.
b. What is the value of the calculated test statistic ( Z )?
c. State your conclusion.