condition mean min max ZT0-3 12.55 12.55 12.55 ZT4-7 11.3 11.3 11.3 ZT8-11 7.8 7.8 7.8 ZT12-15 5.8 5.8 5.8 ZT16-19 23.6 23.6 23.6 ZT20-23 14.3 14.3 14.3