Investigate hypothesis that number of crimes is related to police expenditures because states with higher crime rates are likely to raise their police force, thereby spending more on the number of officers on street.
A. Deveop a scatter diagram of number of crimes and police expenditures, with number of crimes as the predicitor variable. What can you say regarding the relationship between these two variables based upon the scatterplot?
B. Determine the least-squares regression equation that predicts police expenditures from number of crimes. Determine the slope? What is the intercept?
C. Compute the coefficient of determination (r2), and provide an interpretation.
D. If the number of crimes raised by 2,000 for a state, by how much would you predict the police expenditures to increase?
E. Does it make sense to predict police expenditures when number of crimes is equal to zero? Why or Why not?
Data Set: Police expenditures are in millions
State Nbr of crimes (per 1000,000 population) Police expenditures
Maine 2,635 221
New Hamp. 2,013 274
Vermont 2,442 136
Mass. 2,838 1,637
Rhod Island 2,815 286