condition mean min max ZT0-3 19.143614 19.143614 19.143614 ZT4-7 12.8740145 12.8740145 12.8740145 ZT8-11 10.131881 10.131881 10.131881 ZT12-15 13.6058795 13.6058795 13.6058795 ZT16-19 17.6162965 17.6162965 17.6162965 ZT20-23 21.7430775 21.7430775 21.7430775