Sample
Sample comprises 3236 (1659 boys, 1577 girls) students studying in upper primary to higher secondary classes. There were 1461 (808 Boys, 653 girls) standard 5-7 pupils and 1000 (501 boys, 499 girls) standard 8-9 students from 14 upper primary and secondary schools each; and, 775 (350 boys, 425 girls) students of 12th standard from 15 higher secondary schools of Kozhikode district of Kerala. Sampling used proportionate stratified random technique giving due weightage to school locality and type of management.