condition mean min max ZT0-3 22.05 22.05 22.05 ZT4-7 6.8 6.8 6.8 ZT8-11 5.75 5.75 5.75 ZT12-15 7.300000000000001 7.300000000000001 7.300000000000001 ZT16-19 27.049999999999997 27.049999999999997 27.049999999999997 ZT20-23 5.75 5.75 5.75