condition mean min max ZT0-3 12.45 12.45 12.45 ZT4-7 14.7 14.7 14.7 ZT8-11 21.7 21.7 21.7 ZT12-15 33.5 33.5 33.5 ZT16-19 17.700000000000003 17.700000000000003 17.700000000000003 ZT20-23 27.25 27.25 27.25