condition mean min max ZT0-3 1.938535 1.938535 1.938535 ZT4-7 1.856615 1.856615 1.856615 ZT8-11 2.7190950000000003 2.7190950000000003 2.7190950000000003 ZT12-15 1.9941900000000001 1.9941900000000001 1.9941900000000001 ZT16-19 2.96946 2.96946 2.96946 ZT20-23 1.55017 1.55017 1.55017