condition mean min max ZT0-3 14.45328 2.85924 21.1774 ZT4-7 3.5139750000000003 3.5139750000000003 3.5139750000000003 ZT8-11 4.96571 4.96571 4.96571 ZT12-15 12.8349525 9.664905000000001 16.005 ZT16-19 17.29315 17.29315 17.29315 ZT20-23 21.6766 21.6766 21.6766