condition mean min max ZT0-3 4.9 4.9 4.9 ZT4-7 17.3 17.3 17.3 ZT8-11 14.45 14.45 14.45 ZT12-15 39.25 39.25 39.25 ZT16-19 17.700000000000003 17.700000000000003 17.700000000000003 ZT20-23 9.25 9.25 9.25