About half of the police officers in Pearson, Ontario, have completed a special course in investigative procedures. Has the course increased their efficiency in clearing crimes by arrest? The...

About half of the police officers in Pearson, Ontario, have completed a special course in investigative procedures. Has the course increased their efficiency in clearing crimes by arrest? The proportions of cases cleared by arrest for samples of trained and untrained officers are reported below.

A large counselling centre needs to evaluate several experimental programs. Write a paragraph summarizing the results of these tests. Did the new programs work?

a. One program is designed for divorce counselling; the key feature of the program is its counsellors, who are married couples working in teams. About half of all clients have been randomly assigned to this special program and half to the regular program, and the proportion of cases that eventually ended in divorce has been recorded for both. The results for random samples of couples from both programs are reported below. In terms of preventing divorce, did the new program work?

b. The agency is also experimenting with peer counselling for depressed children. About half of all clients were randomly assigned to peer counselling. After the program had run for a year, a random sample of children from the new program was compared with a random sample of children who did not receive peer counselling. In terms of the percentage who were judged to be “much improved,” did the new program work?