condition mean min max ZT0-3 2.45 2.45 2.45 ZT4-7 9.0 9.0 9.0 ZT8-11 2.6 2.6 2.6 ZT12-15 4.4 4.4 4.4 ZT16-19 10.0 10.0 10.0 ZT20-23 11.9 11.9 11.9