Discussion:
Q: Community policing strategies have been useful in some jurisdictions to reduce crime. As Police Captain, you wish to run an experiment to see whether it will work in your city. In each of 10 neighborhoods you record the number of arrests for violent offenses for 90 days prior to implementing a community policing strategy and for 90 days after the program has been running for 6 months.
Neighborhood Before After
1 55 42
2 62 59
3 57 58
4 69 60
5 65 58
6 88 81
7 76 70
8 55 51
9 54 56
10 65 63
SUM
646 598
Did community policing work? What are the null and alternative hypotheses? What is your conclusion [use alpha of 1%]?