condition mean min max ZT0-3 8.76744 8.76744 8.76744 ZT4-7 6.8460350000000005 6.8460350000000005 6.8460350000000005 ZT8-11 6.864275 6.864275 6.864275 ZT12-15 9.102865 9.102865 9.102865 ZT16-19 12.81715 12.81715 12.81715 ZT20-23 10.028855 10.028855 10.028855