condition mean min max ZT0-3 2.45 2.45 2.45 ZT4-7 1.1 1.1 1.1 ZT8-11 20.05 20.05 20.05 ZT12-15 1.6 1.6 1.6 ZT16-19 7.550000000000001 7.550000000000001 7.550000000000001 ZT20-23 3.05 3.05 3.05