condition mean min max ZT0-3 10.850000000000001 10.850000000000001 10.850000000000001 ZT4-7 1.6 1.6 1.6 ZT8-11 5.4 5.4 5.4 ZT12-15 9.2 9.2 9.2 ZT16-19 4.2 4.2 4.2 ZT20-23 14.55 14.55 14.55