condition mean min max ZT0-3 2.3 2.3 2.3 ZT4-7 4.2 4.2 4.2 ZT8-11 9.3 9.3 9.3 ZT12-15 2.1 2.1 2.1 ZT16-19 10.85 10.85 10.85 ZT20-23 2.7 2.7 2.7