condition mean min max ZT0-3 2.45 2.45 2.45 ZT4-7 2.1 2.1 2.1 ZT8-11 2.6 2.6 2.6 ZT12-15 7.449999999999999 7.449999999999999 7.449999999999999 ZT16-19 4.3 4.3 4.3 ZT20-23 1.9 1.9 1.9