A psychologist operating a group home for delinquent adolescents needs to show that it is successful at reducing delinquency. He samples nine adolescents living at home whom the police have identified as having problems, nine similar adolescents living in foster homes, and nine adolescents living in the group home. The severity of each adolescent's problem, where one is the least severe and ten is the most severe, has also been recorded. As an indicator of the success of the program, the psychologist uses the number of days truant during the previous semester, which is readily available from school records.

Please name each variable and state what that variable's scale of measurement is.