condition mean min max ZT0-3 11.25 11.25 11.25 ZT4-7 4.1 4.1 4.1 ZT8-11 7.2 7.2 7.2 ZT12-15 4.3 4.3 4.3 ZT16-19 18.3 18.3 18.3 ZT20-23 2.85 2.85 2.85