condition mean min max ZT0-3 4.105216666666667 3.33946 5.451935000000001 ZT4-7 7.871905 7.871905 7.871905 ZT8-11 3.335115 3.335115 3.335115 ZT12-15 6.486084999999999 4.3468599999999995 8.625309999999999 ZT16-19 6.619165 6.619165 6.619165 ZT20-23 4.18696 4.18696 4.18696