Sample No.

Site I

Site II

Site III

WHO standards

1

8.161

8.189

8.327

2

8.057

8.42

8.37

3

7.891

7.83

8.365

4

8.025

8.135

8.401

6.5 to 9.5

5

7.68

8.126

8.192

Average (Y) and standard deviation

7.962 ± 0.185

8.140 ± 0.210

8.331 ± 0.082