condition mean min max ZT0-3 7.6054475 7.584530000000001 7.626365 ZT4-7 8.69632 8.69632 8.69632 ZT8-11 14.14895 14.14895 14.14895 ZT12-15 0 0 0 ZT16-19 11.12745 11.12745 11.12745 ZT20-23 9.751135 9.751135 9.751135