1).

Assume that the international average homicide victimization rate is 2.92 (per 100,000). In a sample of 24 industrialized nations, LaFree and Drass (2002) found that the mean homicide victimization rate was 1.49 (per 100,000; standard deviation = 0.44). Perform a hypothesis test to determine if the mean homicide rate in industrialized nations is different than the international average. Use a 0.05 level of statistical significance.

Which distribution, z or t, will you use?

t-statistic; Studentstdistribution

z-statistic; Standard normal distribution

2).Some research suggests that police officers are more likely to make an arrest in the presence of bystanders. If mentally disordered suspects attract more attention from bystanders, they may be more likely to be arrested than nonmentally disordered suspects. Assume that the average number of bystanders when police encounter a suspect is 3.58. In a sample of 20police encounters with mentally disordered suspects, Engel and Silver (2001) found an average of 7.03 bystanders (standard deviation = 9.42). Perform a hypothesis test to determine if there are more bystanders when the suspect is mentally disordered. Use a 0.01 level of statistical significance.

Which distribution, z or t, will you use?

t-statistic; Students t distribution

z-statistic; Standard normal distribution