condition mean min max ZT0-3 3.15 3.15 3.15 ZT4-7 1.4 1.4 1.4 ZT8-11 7.300000000000001 7.300000000000001 7.300000000000001 ZT12-15 4.95 4.95 4.95 ZT16-19 3.2 3.2 3.2 ZT20-23 3.9499999999999997 3.9499999999999997 3.9499999999999997