condition mean min max ZT0-3 6.45 6.45 6.45 ZT4-7 2.1 2.1 2.1 ZT8-11 4.1 4.1 4.1 ZT12-15 0.95 0.95 0.95 ZT16-19 4.6000000000000005 4.6000000000000005 4.6000000000000005 ZT20-23 5.0 5.0 5.0