When a police officer responds to a call for help in a case of spousal abuse,what should the officer do? A randomized controlled experiment in Charlotte,North Carolina,studied three police responses to spousal abuse: advise and possibly separate the couple,issue a citation to the offender,and arrest the offender.The effectiveness of the three responses was determined by re-arrest rates.The table below shows these rates. Suppose we wish to test the null hypothesis that the proportions of subsequent arrests are the same regardless of the treatment assigned.Under the null hypothesis,what is the expected number of times no subsequent arrest would occur for the treatment "Advise/separate"?
A)177
B)181
C)187
D)543

Question

When a police officer responds to a call for help in a case of spousal abuse,what should the officer do? A randomized controlled experiment in Charlotte,North Carolina,studied three police responses to spousal abuse: advise and possibly separate the couple,issue a citation to the offender,and arrest the offender.The effectiveness of the three responses was determined by re-arrest rates.The table below shows these rates.  Suppose we wish to test the null hypothesis that the proportions of subsequent arrests are the same regardless of the treatment assigned.Under the null hypothesis,what is the expected number of times no subsequent arrest would occur for the treatment "Advise/separate"?
A)177 
B)181 
C)187 
D)543

Quizplus · Accepted Answer

Under the null hypothesis, the expected number of times no subsequent arrest would occur for the treatment "Advise/separate" is equal to the total number of cases in that treatment group, which is 177. This can be calculated by multiplying the total number of cases (348) by the proportion of cases with no subsequent arrest in the "Advise/separate" group (51%).

When a Police Officer Responds to a Call for Help