condition mean min max ZT0-3 1.85 1.85 1.85 ZT4-7 3.5 3.5 3.5 ZT8-11 1.0 1.0 1.0 ZT12-15 5.6000000000000005 5.6000000000000005 5.6000000000000005 ZT16-19 5.55 5.55 5.55 ZT20-23 6.9 6.9 6.9