condition mean min max ZT0-3 14.65 14.65 14.65 ZT4-7 8.2 8.2 8.2 ZT8-11 21.9 21.9 21.9 ZT12-15 7.6 7.6 7.6 ZT16-19 6.0 6.0 6.0 ZT20-23 3.4 3.4 3.4