condition mean min max ZT0-3 4.4909783333333335 3.9129000000000005 5.020575 ZT4-7 8.195555 8.195555 8.195555 ZT8-11 6.86719 6.86719 6.86719 ZT12-15 21.151825 19.8061 22.497549999999997 ZT16-19 11.90965 11.90965 11.90965 ZT20-23 9.93849 9.93849 9.93849