condition mean min max ZT0-3 482.847441 482.847441 482.847441 ZT4-7 394.48617 394.48617 394.48617 ZT8-11 373.05138999999997 373.05138999999997 373.05138999999997 ZT12-15 447.0732905 447.0732905 447.0732905 ZT16-19 510.589039 510.589039 510.589039 ZT20-23 594.6744755 594.6744755 594.6744755