condition mean min max ZT0-3 2.7 2.7 2.7 ZT4-7 1.1 1.1 1.1 ZT8-11 2.7 2.7 2.7 ZT12-15 2.8 2.8 2.8 ZT16-19 3.9499999999999997 3.9499999999999997 3.9499999999999997 ZT20-23 3.7 3.7 3.7