condition mean min max ZT0-3 1.7917278333333333 1.0714535 2.7675099999999997 ZT4-7 5.13153 5.13153 5.13153 ZT8-11 10.660699999999999 10.660699999999999 10.660699999999999 ZT12-15 18.163975 14.46195 21.866 ZT16-19 8.46001 8.46001 8.46001 ZT20-23 2.44322 2.44322 2.44322