Specimen Number

1

2

3

4

5

6

7

8

9

10

Means

(pre-test) (HB)

38

32

41

39

35

37

37

35

38

40

37.2

(post-test) (HB)

40

36

47

47

42

45

47

36

48

52

44

Hardness change (HB)

2

4

6

8

7

8

10

1

10

12

6.8

Change%

5.26

12.50

14.63

20.51

20

21.62

27.03

2.86

26.32

30

18.28