condition mean min max ZT0-3 2.1500000000000004 2.1500000000000004 2.1500000000000004 ZT4-7 9.0 9.0 9.0 ZT8-11 12.7 12.7 12.7 ZT12-15 8.25 8.25 8.25 ZT16-19 9.9 9.9 9.9 ZT20-23 5.65 5.65 5.65