condition mean min max ZT0-3 3.041885 2.983975 3.0997950000000003 ZT4-7 5.498725 5.498725 5.498725 ZT8-11 5.31522 5.31522 5.31522 ZT12-15 0 0 0 ZT16-19 5.213625 5.213625 5.213625 ZT20-23 6.226815 6.226815 6.226815