Group

n

0 w

2 w

4 w

6 w

HFZS

35

7.44 ± 0.27

6.65 ± 0.41

6.38 ± 0.26

6.98 ± 0.20

HF

32

7.42 ± 0.33

6.59 ± 0.36

6.55 ± 0.37

6.63 ± 0.27**

ZS

31

7.39 ± 0.31

6.71 ± 0.31

6.67 ± 0.33△△

6.52 ± 0.23△△