condition mean min max ZT0-3 7.4 7.4 7.4 ZT4-7 1.5 1.5 1.5 ZT8-11 1.65 1.65 1.65 ZT12-15 14.5 14.5 14.5 ZT16-19 3.9499999999999997 3.9499999999999997 3.9499999999999997 ZT20-23 7.8999999999999995 7.8999999999999995 7.8999999999999995