condition mean min max ZT0-3 3.4000000000000004 3.4000000000000004 3.4000000000000004 ZT4-7 2.0 2.0 2.0 ZT8-11 5.5 5.5 5.5 ZT12-15 3.65 3.65 3.65 ZT16-19 4.0 4.0 4.0 ZT20-23 4.45 4.45 4.45