condition mean min max ZT0-3 2.1362766666666664 1.405235 2.7720399999999996 ZT4-7 1.21813 1.21813 1.21813 ZT8-11 2.086305 2.086305 2.086305 ZT12-15 2.7797575 2.24486 3.314655 ZT16-19 0.713945 0.713945 0.713945 ZT20-23 3.37961 3.37961 3.37961