condition mean min max ZT0-3 10.7 10.7 10.7 ZT4-7 8.5 8.5 8.5 ZT8-11 18.05 18.05 18.05 ZT12-15 15.95 15.95 15.95 ZT16-19 2.1500000000000004 2.1500000000000004 2.1500000000000004 ZT20-23 13.75 13.75 13.75