A researcher records the annual number of serious crimes and the amount spent on crime prevention for several small towns, medium cities, and large cities across the country. The resulting data show a strong positive correlation between the number of serious crimes and the amount spent on crime prevention. However, the researcher suspects that the positive correlation is actually caused by population; as population increases, both the amount spent on crime prevention and the number of crimes also increases. If population is controlled, there probably should be a negative correlation between the amount spent on crime prevention and the number of serious crimes. The following data show the pattern of results obtained. Note that the municipalities are coded in three categories. Use a partial correlation, holding population constant, to measure the true relationship between crime rate and the amount spent on prevention.

Transcribed Image Text:

Number of Amount for Population Size Crimes Prevention 3 1 4 3 4 1 11 2 9. 12 2 11 2 12 9. 2 13 16 3 14 17 3 16 13 17 14 3