"A study from 1976 to 1989 found that young Black males engaged in more violent crime than young White males. But when the researchers compared only employed young males of both races, the differences in violent behavior vanished. Or, as the Urban Institute stated in a more recent report on long-term unemployment, 'Communities with a higher share of long-term unemployed workers also tend to have higher rates of crime and violence.'"

QUESTION

.How might the researchers have used data to draw their conclusions? What statisticscould they have used? What are the variables? What might the researchers have done with those variables?