condition mean min max ZT0-3 4.9 4.9 4.9 ZT4-7 28.2 28.2 28.2 ZT8-11 22.3 22.3 22.3 ZT12-15 8.0 8.0 8.0 ZT16-19 23.450000000000003 23.450000000000003 23.450000000000003 ZT20-23 5.65 5.65 5.65