condition mean min max ZT0-3 4.350294999999999 4.350294999999999 4.350294999999999 ZT4-7 2.672675 2.672675 2.672675 ZT8-11 3.64954 3.64954 3.64954 ZT12-15 7.1363199999999996 7.1363199999999996 7.1363199999999996 ZT16-19 6.358625 6.358625 6.358625 ZT20-23 6.689095 6.689095 6.689095