condition mean min max ZT0-3 2.9226966666666665 2.1462149999999998 3.373475 ZT4-7 2.626295 2.626295 2.626295 ZT8-11 1.9433449999999999 1.9433449999999999 1.9433449999999999 ZT12-15 4.00119 3.8442950000000002 4.158085 ZT16-19 4.109505 4.109505 4.109505 ZT20-23 4.13279 4.13279 4.13279