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

Say we have a sample of 101 cases, with a mean of 55.04 and a standard deviation of 9.86. We want to test whether our sample mean is different than the population mean of 57. What is your test statistic?

-1.998

-3.311

-1.184

-1.612

A researcher wants to test achievement scores for home schooled 4^thgraders.He knows that the population average for achievement scores of students who attend school is 250.He samples 110 home schooled 4^thgraders and finds and achievement level of 272 with a standard deviation of 10.Using a 0.01 significance level, the research finds the following:

H₁:250

z: +/- 2.57

z = 2.20

Based on this information, what would you conclude?

Fail to reject the null hypothesis

Reject the null hypothesis