condition mean min max ZT0-3 2.9 2.9 2.9 ZT4-7 22.5 22.5 22.5 ZT8-11 3.8 3.8 3.8 ZT12-15 47.3 47.3 47.3 ZT16-19 19.900000000000002 19.900000000000002 19.900000000000002 ZT20-23 30.2 30.2 30.2