condition mean min max ZT0-3 5.550000000000001 5.550000000000001 5.550000000000001 ZT4-7 2.5 2.5 2.5 ZT8-11 9.2 9.2 9.2 ZT12-15 6.300000000000001 6.300000000000001 6.300000000000001 ZT16-19 27.45 27.45 27.45 ZT20-23 7.9 7.9 7.9