Working years

N

Speech

frequency

3 kHz

4 kHz

6 kHz

3 kHz + 4 kHz

3 kHz + 6 kHz

4 kHz + 6 kHz

3 kHz + 4 kHz + 6 kHz

3 - 5

38

29.78 ± 9.83

31.70 ± 9.78

32.28 ± 9.42

32.32 ± 9.58

32.03 ± 9.58

32.07 ± 9.63

32.33 ± 9.48

32.12 ± 9.55

6 - 10

67

30.49 ± 9.28

32.31 ± 9.17

32.72 ± 8.53

33.39 ± 8.66

32.56 ± 8.83

32.90 ± 8.85

33.09 ± 8.57

32.83 ± 8.72

>10

63

31.90 ± 13.55

33.99 ± 13.04

34.47 ± 12.59

34.73 ± 12.99

34.26 ± 12.81

34.40 ± 12.98

34.74 ± 12.77

34.40 ± 12.85

Total

168

30.74 ± 11.24

32.70 ± 10.98

33.20 ± 10.54*

33.46 ± 10.80*

32.98 ± 10.75

33.13 ± 10.84*

33.57 ± 10.65*

33.14 ± 10.74*