condition mean min max ZT0-3 2.301805 2.209165 2.39487 ZT4-7 2.4367900000000002 2.4367900000000002 2.4367900000000002 ZT8-11 2.04489 2.04489 2.04489 ZT12-15 1.927615 1.8727900000000002 1.98244 ZT16-19 2.7772699999999997 2.7772699999999997 2.7772699999999997 ZT20-23 3.34351 3.34351 3.34351