condition mean min max ZT0-3 8.033946666666667 4.8715399999999995 10.722185 ZT4-7 2.833065 2.833065 2.833065 ZT8-11 4.244125 4.244125 4.244125 ZT12-15 5.4057825 5.02689 5.784675 ZT16-19 7.972045 7.972045 7.972045 ZT20-23 8.707609999999999 8.707609999999999 8.707609999999999