Pre-intervention

Post-intervention

Group

Number of cases

Class I

Class II

Class III

Grade IV

Class I

Class II

Class III

Grade IV

Control group

30

4 (13)

14 (47)

8 (27)

4 (13)

11 (37)

12 (40)

5 (17)

2 (6)

Observation group

30

3 (10)

15 (50)

9 (30)

3 (10)

17 (57)

13 (43)

0 (0)

0 (0)

Z value

0.382

2.218

P value

0.612

0.028