condition mean min max ZT0-3 11.3 11.3 11.3 ZT4-7 6.8 6.8 6.8 ZT8-11 14.5 14.5 14.5 ZT12-15 12.0 12.0 12.0 ZT16-19 3.65 3.65 3.65 ZT20-23 7.4 7.4 7.4