condition mean min max ZT0-3 17.3 17.3 17.3 ZT4-7 7.8 7.8 7.8 ZT8-11 5.15 5.15 5.15 ZT12-15 1.2 1.2 1.2 ZT16-19 21.2 21.2 21.2 ZT20-23 6.4 6.4 6.4