condition mean min max ZT0-3 15.7 15.7 15.7 ZT4-7 25.4 25.4 25.4 ZT8-11 24.25 24.25 24.25 ZT12-15 18.75 18.75 18.75 ZT16-19 29.700000000000003 29.700000000000003 29.700000000000003 ZT20-23 49.1 49.1 49.1