dear Gul i think the material under the heading of research methods in sociology you can find the answer.....n scale is a type of instrument designed 2 measure any aspect of human life esp human social n psychological attributes are measured.....scales may be of many types like 3 point i.e...yes ,no, dont know...or may be even 5 or 7 point rating scales,,,,Likert 5 point rating scale is v popular n imp as well........
seniors correct me where i m wrong
REGARDS